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Schofield P, Bradicich A, Gurrola RM, Zhang Y, Brown TD, Pharr M, Shamberger PJ, Banerjee S. Harnessing the Metal-Insulator Transition of VO 2 in Neuromorphic Computing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205294. [PMID: 36036767 DOI: 10.1002/adma.202205294] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Future-generation neuromorphic computing seeks to overcome the limitations of von Neumann architectures by colocating logic and memory functions, thereby emulating the function of neurons and synapses in the human brain. Despite remarkable demonstrations of high-fidelity neuronal emulation, the predictive design of neuromorphic circuits starting from knowledge of material transformations remains challenging. VO2 is an attractive candidate since it manifests a near-room-temperature, discontinuous, and hysteretic metal-insulator transition. The transition provides a nonlinear dynamical response to input signals, as needed to construct neuronal circuit elements. Strategies for tuning the transformation characteristics of VO2 based on modification of material properties, interfacial structure, and field couplings, are discussed. Dynamical modulation of transformation characteristics through in situ processing is discussed as a means of imbuing synaptic function. Mechanistic understanding of site-selective modification; external, epitaxial, and chemical strain; defect dynamics; and interfacial field coupling in modifying local atomistic structure, the implications therein for electronic structure, and ultimately, the tuning of transformation characteristics, is emphasized. Opportunities are highlighted for inverse design and for using design principles related to thermodynamics and kinetics of electronic transitions learned from VO2 to inform the design of new Mott materials, as well as to go beyond energy-efficient computation to manifest intelligence.
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Affiliation(s)
- Parker Schofield
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Adelaide Bradicich
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Rebeca M Gurrola
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Yuwei Zhang
- Department of Mechanical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | | | - Matt Pharr
- Department of Mechanical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Patrick J Shamberger
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Sarbajit Banerjee
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
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2
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Lappalainen J, Kangaspuoskari M. Interface Effects of Strain-Energy Potentials on Phase Transition Characteristics of VO 2 Thin-Films. ACS OMEGA 2023; 8:21083-21095. [PMID: 37323390 PMCID: PMC10268292 DOI: 10.1021/acsomega.3c01966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/16/2023] [Indexed: 06/17/2023]
Abstract
Metal-insulator-transition (MIT) of VO2 has attracted strong attention as a potential phenomenon to be utilized in nanostructured devices. Dynamics of MIT phase transition determines the feasibility of VO2 material properties in various applications, for example, photonic components, sensors, MEMS actuators, and neuromorphic computing. However, conventional interface strain model predicts the MIT effect accurately for bulk, but fairly for the thin films, and thus, a new model is needed. It was found that the VO2 thin film-substrate interface plays a crucial role in determining transition dynamics properties. In VO2 thin films on different substrates, coexistence of insulator-state polymorph phases, dislocations, and a few unit cell reconstruction layer form an interface structure minimizing strain energy by the increase of structural complexity. As a consequence, MIT temperature and hysteresis of structure increased as the transition enthalpy of the interface increased. Thus, the process does not obey the conventional Clausius-Clapeyron law anymore. A new model is proposed for residual strain energy potentials by implementing a modified Cauchy strain. Experimental results confirm that the MIT effect in constrained VO2 thin films is induced through the Peierls mechanism. The developed model provides tools for strain engineering in the atomic scale for crystal potential distortion effects in nanotechnology, such as topological quantum devices.
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3
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Zhang W, Wu X, Li L, Zou C, Chen Y. Fabrication of a VO 2-Based Tunable Metasurface by Electric-Field Scanning Probe Lithography with Precise Depth Control. ACS APPLIED MATERIALS & INTERFACES 2023; 15:13517-13525. [PMID: 36856296 DOI: 10.1021/acsami.2c21935] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Vanadium dioxide (VO2) is widely employed in developing tunable optoelectronic devices due to its significant changes in optical and electric properties upon phase transition. To fabricate the VO2-based functional devices down to the micro/nanoscale, a high-resolution processing technique is in demand. Scanning probe lithography (SPL) on the basis of a tip-induced electric field provides a promising approach for prototyping. Here, we demonstrated a precise VO2 etching strategy by direct writing on a VO2 film with a negative tip bias and subsequent sonication removal of the written area. The effects of bias voltage, sonication, and thermal treatment as well as the mechanical difference between the tip-modulated area and the pristine VO2 film were investigated systematically. The results show that VO2 can be etched layer by layer via alternately repeating tip modulation and sonication, and arbitrary patterns can be written. Based on this route, we designed a kind of metasurface by arranging VO2-gold nanoblocks with different sizes and heights for spectrally selective tunable reflectivity in near- and mid-infrared. This electric-field SPL method demonstrates the prominent advantages of high resolution down to several tens of nanometers, quasi-3D patterning, and resist-free maskless direct writing, which should be applicable for prototyping other micro/nanodevices.
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Affiliation(s)
- Wenhao Zhang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230027, China
| | - Xiqi Wu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230027, China
| | - Liang Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Chongwen Zou
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Yuhang Chen
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230027, China
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4
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Hong WK, Jang HS, Yoon J, Choi WJ. Modulation of Switching Characteristics in a Single VO 2 Nanobeam with Interfacial Strain via the Interconnection of Multiple Nanoscale Channels. ACS APPLIED MATERIALS & INTERFACES 2023; 15:11296-11303. [PMID: 36787543 DOI: 10.1021/acsami.2c21367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We demonstrate the modulation of electrical switching properties through the interconnection of multiple nanoscale channels (∼600 nm) in a single VO2 nanobeam with a coexisting metal-insulator (M-I) domain configuration during phase transition. The Raman scattering characteristics of the synthesized VO2 nanobeams provide evidence that substrate-induced interfacial strain can be inhomogeneously distributed along the length of the nanobeam. Interestingly, the nanoscale VO2 devices with the same channel length and width exhibit distinct differences in hysteric current-voltage characteristics, which are explained by theoretical calculations of resistance change combined with Joule heating simulations of the nanoscale VO2 channels. The observed results can be attributed to the difference in the spatial distribution and fraction ratios of M-I domains due to interfacial strain in the nanoscale VO2 channels during the metal-insulator transition process. Moreover, we demonstrate the electrically activated resistive switching characteristics based on the hysteresis behaviors of the interconnected nanoscale channels, implying the possibility of manipulating multiple resistive states. Our results may offer insights into the nanoscale engineering of correlated phases in VO2 as the key materials of neuromorphic computing for which nonlinear conductance is essential.
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Affiliation(s)
- Woong-Ki Hong
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Hun Soo Jang
- Chemical Materials Solutions Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Jongwon Yoon
- Department of Energy & Electronic Materials, Surface & Nano Materials Division, Korea Institute of Materials Science, Changwon-si, Gyeongsangnam-do 51508, Republic of Korea
| | - Woo Jin Choi
- Chemical Materials Solutions Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
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5
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Shestakov VA, Yakovkina LV, Kichay VN. Synthesis of Vanadium Dioxide from a Mixture of Vanadyl Acetylacetonate and Oxygen: Simulation and Experiment. RUSS J INORG CHEM+ 2022. [DOI: 10.1134/s0036023622601179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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6
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Zheng C, Simpson RE, Tang K, Ke Y, Nemati A, Zhang Q, Hu G, Lee C, Teng J, Yang JKW, Wu J, Qiu CW. Enabling Active Nanotechnologies by Phase Transition: From Electronics, Photonics to Thermotics. Chem Rev 2022; 122:15450-15500. [PMID: 35894820 DOI: 10.1021/acs.chemrev.2c00171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phase transitions can occur in certain materials such as transition metal oxides (TMOs) and chalcogenides when there is a change in external conditions such as temperature and pressure. Along with phase transitions in these phase change materials (PCMs) come dramatic contrasts in various physical properties, which can be engineered to manipulate electrons, photons, polaritons, and phonons at the nanoscale, offering new opportunities for reconfigurable, active nanodevices. In this review, we particularly discuss phase-transition-enabled active nanotechnologies in nonvolatile electrical memory, tunable metamaterials, and metasurfaces for manipulation of both free-space photons and in-plane polaritons, and multifunctional emissivity control in the infrared (IR) spectrum. The fundamentals of PCMs are first introduced to explain the origins and principles of phase transitions. Thereafter, we discuss multiphysical nanodevices for electronic, photonic, and thermal management, attesting to the broad applications and exciting promises of PCMs. Emerging trends and valuable applications in all-optical neuromorphic devices, thermal data storage, and encryption are outlined in the end.
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Affiliation(s)
- Chunqi Zheng
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore.,NUS Graduate School, National University of Singapore, Singapore 119077, Singapore
| | - Robert E Simpson
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore
| | - Kechao Tang
- Key Laboratory of Microelectronic Devices and Circuits (MOE), School of Integrated Circuits, Peking University, Beijing 100871, China
| | - Yujie Ke
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore
| | - Arash Nemati
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Qing Zhang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Guangwei Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Chengkuo Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Jinghua Teng
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Joel K W Yang
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore.,Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, and Lawrence Berkeley National Laboratory, California 94720, United States
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
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7
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Shayapov VR, Kichai VN, Yakovkina LV, Korolkov IV. CRYSTAL TEXTURE AND MECHANICAL STRESSES IN VO2 FILMS OBTAINED BY MOCVD. J STRUCT CHEM+ 2022. [DOI: 10.1134/s0022476622020044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Kim A, Lim SY, Park JH, Chung JS, Cheong H, Ko C, Yoon JG, Yang SM. Nanoscale mapping of temperature-dependent conduction in an epitaxial VO 2 film grown on an Al 2O 3 substrate. RSC Adv 2022; 12:23039-23047. [PMID: 36090401 PMCID: PMC9379556 DOI: 10.1039/d2ra02803d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022] Open
Abstract
Vanadium dioxide (VO2) is one of the extensively studied strongly correlated oxides due to its intriguing insulator–metal transition near room temperature. In this work, we investigated temperature-dependent nanoscale conduction in an epitaxial VO2 film grown on an Al2O3 substrate using conductive-atomic force microscopy (C-AFM). We observed that only the regions near the grain boundaries are conductive, producing intriguing donut patterns in C-AFM images. Such donut patterns were observed in the entire measured temperature range (300–355 K). The current values near the grain boundaries increased by approximately two orders of magnitude with an increase in the temperature, which is consistent with the macroscopic transport data. The spatially-varied conduction behavior is ascribed to the coexistence of different monoclinic phases, i.e., M1 and M2 phases, based on the results of temperature-dependent Raman spectroscopy. Furthermore, we investigated the conduction mechanism in the relatively conductive M1 phase regions at room temperature using current–voltage (I–V) spectroscopy and deep data analysis. Bayesian linear unmixing and k-means clustering showed three distinct types of conduction behavior, which classical C-AFM cannot resolve. We found that the conduction in the M1 phase regions can be explained by the Poole–Frenkel mechanism. This work provides deep insight into IMT behavior in the epitaxial VO2 thin film at the nanoscale, especially the coexistence and evolution of the M1 and M2 phases. This work also highlights that I–V spectroscopy combined with deep data analysis is very powerful in investigating local transport in complex oxides and various material systems. We investigated temperature-dependent nanoscale conduction in an epitaxial VO2 film grown on an Al2O3 substrate using conductive-atomic force microscopy and deep data analysis.![]()
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Affiliation(s)
- Ahyoung Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Soo Yeon Lim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Jung Hyun Park
- Department of Physics, Soongsil University, Seoul 07027, Korea
| | - Jin-Seok Chung
- Department of Physics, Soongsil University, Seoul 07027, Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Changhyun Ko
- Department of Applied Physics, College of Engineering, Sookmyung Women's University, Seoul 04310, Korea
| | - Jong-Gul Yoon
- Department of Physics and Electronic Materials Engineering, University of Suwon, Gyeonggi-do 18323, Korea
| | - Sang Mo Yang
- Department of Physics, Sogang University, Seoul 04107, Korea
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9
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Santos AJ, Escanciano M, Suárez-Llorens A, Pilar Yeste M, Morales FM. A Novel Route for the Easy Production of Thermochromic VO 2 Nanoparticles. Chemistry 2021; 27:16662-16669. [PMID: 34661929 PMCID: PMC9297899 DOI: 10.1002/chem.202102566] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Indexed: 11/09/2022]
Abstract
In this work, a simple, fast and dry method for the fabrication of a thermochromic product with a high load of VO2(M1) consisting of the controlled heat treatment of pure vanadium nanoparticles in air is presented. After a complete design of experiments, it is concluded that the most direct way to attain the maximum transformation of V into VO2(M1) consists of one cycle with a fast heating ramp of 42 °C s−1, followed by keeping 700 °C for 530–600 seconds, and a subsequent cooling at 0.05 °C s−1. Careful examination of these results lead to a second optimum, even more suitable for industrial production (quicker and less energy‐intensive because of its lower temperatures and shorter times), consisting of subjecting V to two consecutive cycles of temperatures and times (625 °C for 5 minutes) with similar preheating (42 °C s−1) but a much faster postcooling (∼ 8 °C s−1). These green reactions only use the power for heating a tube open to atmosphere and a vanadium precursor; without assistance of reactive gases or catalysts, and no special vacuum or pressure requirements. The best products present similar thermochromic properties but higher thermal stability than commercial VO2 particles. These methods can be combined with VO2 doping.
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Affiliation(s)
- Antonio J Santos
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cadiz, Puerto Real, Cádiz, Spain.,Department of Materials Science, Metallurgical Engineering and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, Cádiz, Spain
| | - Marta Escanciano
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cadiz, Puerto Real, Cádiz, Spain.,Department of Materials Science, Metallurgical Engineering and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, Cádiz, Spain
| | - Alfonso Suárez-Llorens
- Department of Statistics and Operative Investigation, Faculty of Sciences, University of Cádiz, Puerto Real, Cádiz, Spain.,INDESS: Institute of Research on Social and Sustainable Development, University of Cádiz, Jerez, Cádiz, Spain
| | - M Pilar Yeste
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cadiz, Puerto Real, Cádiz, Spain.,Department of Materials Science, Metallurgical Engineering and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, Cádiz, Spain
| | - Francisco M Morales
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cadiz, Puerto Real, Cádiz, Spain.,Department of Materials Science, Metallurgical Engineering and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, Cádiz, Spain
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10
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Jiang J, Chen Z, Hu Y, Xiang Y, Zhang L, Wang Y, Wang GC, Shi J. Flexo-photovoltaic effect in MoS 2. NATURE NANOTECHNOLOGY 2021; 16:894-901. [PMID: 34140672 DOI: 10.1038/s41565-021-00919-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
The theoretical Shockley-Queisser limit of photon-electricity conversion in a conventional p-n junction could be potentially overcome by the bulk photovoltaic effect that uniquely occurs in non-centrosymmetric materials. Using strain-gradient engineering, the flexo-photovoltaic effect, that is, the strain-gradient-induced bulk photovoltaic effect, can be activated in centrosymmetric semiconductors, considerably expanding material choices for future sensing and energy applications. Here we report an experimental demonstration of the flexo-photovoltaic effect in an archetypal two-dimensional material, MoS2, by using a strain-gradient engineering approach based on the structural inhomogeneity and phase transition of a hybrid system consisting of MoS2 and VO2. The experimental bulk photovoltaic coefficient in MoS2 is orders of magnitude higher than that in most non-centrosymmetric materials. Our findings unveil the fundamental relation between the flexo-photovoltaic effect and a strain gradient in low-dimensional materials, which could potentially inspire the exploration of new optoelectronic phenomena in strain-gradient-engineered materials.
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Affiliation(s)
- Jie Jiang
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
| | - Zhizhong Chen
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yang Hu
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yu Xiang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Lifu Zhang
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yiping Wang
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Gwo-Ching Wang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Jian Shi
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
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11
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Wang JN, Xiong B, Peng RW, Li CY, Hou BQ, Chen CW, Liu Y, Wang M. Flexible Phase Change Materials for Electrically-Tuned Active Absorbers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2101282. [PMID: 34173329 DOI: 10.1002/smll.202101282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/25/2021] [Indexed: 06/13/2023]
Abstract
Phase change materials (PCMs), such as GeSbTe (GST) alloys and vanadium dioxide (VO2 ), play an important role in dynamically tunable optical metadevices. However, the PCMs usually require high thermal annealing temperatures above 700 K, but most flexible metadevices can only work below 500 K owing to the thermal instability of polymer substrates. This contradiction limits the integration of PCMs into flexible metadevices. Here, a mica sheet is chosen as the chemosynthetic support for VO2 and a smooth and uniformly flexible phase change material (FPCM) is realized. Such FPCMs can withstand high temperatures while remaining mechanically flexible. As an example, a metal-FPCM-metal infrared meta-absorber with mechanical flexibility and electrical tunability is demonstrated. Based on the electrically-tuned phase transition of FPCMs, the infrared absorption of the metadevice is continuously tuned from 20% to 90% as the applied current changes, and it remains quite stable at bending states. The metadevice is bent up to 1500 times, while no visible deterioration is detected. For the first time, the FPCM metastructures are significantly added to the flexible material family, and the FPCM-based metadevices show various application prospects in electrically-tunable conformal metadevices, dynamic flexible photodetectors, and active wearable devices.
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Affiliation(s)
- Jia-Nan Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Bo Xiong
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Ru-Wen Peng
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Cheng-Yao Li
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Ben-Qi Hou
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Chao-Wei Chen
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yu Liu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Mu Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- American Physical Society, Ridge, NY, 11961, USA
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12
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Lee MH, Kalcheim Y, Valle JD, Schuller IK. Controlling Metal-Insulator Transitions in Vanadium Oxide Thin Films by Modifying Oxygen Stoichiometry. ACS APPLIED MATERIALS & INTERFACES 2021; 13:887-896. [PMID: 33351594 DOI: 10.1021/acsami.0c18327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Vanadium oxides are strongly correlated materials which display metal-insulator transitions (MITs) as well as various structural and magnetic properties that depend heavily on oxygen stoichiometry. Therefore, it is crucial to precisely control oxygen stoichiometry in these materials, especially in thin films. This work demonstrates a high-vacuum gas evolution technique which allows for the modification of oxygen concentrations in VOX thin films by carefully tuning the thermodynamic conditions. We were able to control the evolution between VO2, V3O5, and V2O3 phases on sapphire substrates, overcoming the narrow phase stability of adjacent Magnéli phases. A variety of annealing routes were found to achieve the desired phases and eventually control the MIT. The pronounced MIT of the transformed films along with the detailed structural investigations based on X-ray diffraction measurements and X-ray photoelectron spectroscopy show that optimal stoichiometry is obtained and stabilized. Using this technique, we find that the thin-film V-O phase diagram differs from that of the bulk material because of strain and finite size effects. Our study demonstrates new pathways to strategically tune the oxygen stoichiometry in complex oxides and provides a road map for understanding the phase stability of VOX thin films.
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Affiliation(s)
- Min-Han Lee
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, United States
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Yoav Kalcheim
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Javier Del Valle
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Ivan K Schuller
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, United States
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
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13
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Stress-Induced In Situ Modification of Transition Temperature in VO 2 Films Capped by Chalcogenide. MATERIALS 2020; 13:ma13235541. [PMID: 33291745 PMCID: PMC7729558 DOI: 10.3390/ma13235541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 11/16/2022]
Abstract
We attempted to modify the monoclinic–rutile structural phase transition temperature (Ttr) of a VO2 thin film in situ through stress caused by amorphous–crystalline phase change of a chalcogenide layer on it. VO2 films on C- or R-plane Al2O3 substrates were capped by Ge2Sb2Te5 (GST) films by means of rf magnetron sputtering. Ttr of the VO2 layer was evaluated through temperature-controlled measurements of optical reflection intensity and electrical resistance. Crystallization of the GST capping layer was accompanied by a significant drop in Ttr of the VO2 layer underneath, either with or without a SiNx diffusion barrier layer between the two. The shift of Ttr was by ~30 °C for a GST/VO2 bilayered sample with thicknesses of 200/30 nm, and was by ~6 °C for a GST/SiNx/VO2 trilayered sample of 200/10/6 nm. The lowering of Ttr was most probably caused by the volume reduction in GST during the amorphous–crystalline phase change. The stress-induced in in situ modification of Ttr in VO2 films could pave the way for the application of nonvolatile changes of optical properties in optoelectronic devices.
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14
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Lee D, Min T, Lee G, Kim J, Song S, Lee J, Bae JS, Kang H, Lee J, Park S. Understanding the Phase Transition Evolution Mechanism of Partially M2 Phased VO 2 Film by Hydrogen Incorporation. J Phys Chem Lett 2020; 11:9680-9688. [PMID: 33135900 DOI: 10.1021/acs.jpclett.0c02592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Studies on the hydrogen incorporated M1 phase of VO2 film have been widely reported. However, there are few works on an M2 phase of VO2. Recently, the M2 phase in VO2 has received considerable attention due to the possibility of realizing a Mott transition field-effect transistor. By varying the postannealing environment, systematic variations of the M2 phase in (020)-oriented VO2 films grown on Al2O3(0001) were observed. The M2 phase converted to the metallic M1 phase at first and then to the metallic rutile phase after hydrogen annealing (i.e., for H2/N2 mixture and H2 environments). From the diffraction and spectroscopy measurements, the transition is attributed to suppressed electron interactions, not structural modification caused by hydrogen incorporation. Our results suggest the understanding of the phase transition process of the M2 phase by hydrogen incorporation and the possibility of realization of the M2 phased-based Mott transition field-effect transistor.
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Affiliation(s)
- Dooyong Lee
- Department of Physics, Pusan National University, Busan 46241, Korea
- Advanced Nano Surface Research Group, Korea Basic Science Institute, Daejeon 34133, Korea
| | - Taewon Min
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Gongin Lee
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Jiwoong Kim
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Sehwan Song
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Jisung Lee
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon 34133, Korea
| | - Jong-Seong Bae
- Busan Center, Korea Basic Science Institute, Busan 46742, Korea
| | - Haeyong Kang
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Jaekwang Lee
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Sungkyun Park
- Department of Physics, Pusan National University, Busan 46241, Korea
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15
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Fisher B, Patlagan L, Reisner GM. Sliding twin-domains in self-heated needle-like VO 2 single crystals. Sci Rep 2020; 10:6833. [PMID: 32322009 PMCID: PMC7176718 DOI: 10.1038/s41598-020-63694-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/01/2020] [Indexed: 11/09/2022] Open
Abstract
The prototypical metal-insulator transition in VO2 at 340 K is from a high-temperature rutile phase to a low-temperature monoclinic phase. The lower symmetry of the monoclinic structure removes the degeneracy of the two equivalent directions of the tetragonal structure, giving rise to twin domains. Since formation of domain walls require energy most needle-like monoclinic single crystal are single-domain. The mixed metal-insulator state in self-heated needle-like single crystals exhibits various domain patterns, the most remarkable being static insulating triangular domains embedded in the metal and narrow insulating domains sliding along the metallic background in the direction of the electric current. Reported here are results obtained for some rare needle-like twinned VO2 single crystals. Such sample revealed a unique feature: joint static triangular twins emit sliding twin domains, first overlapping and later disjoining. Dark and bright twins and dim metallic background were seen for optimal orientation under a microscope, due to polarization by reflection.
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16
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Ke Y, Wang S, Liu G, Li M, White TJ, Long Y. Vanadium Dioxide: The Multistimuli Responsive Material and Its Applications. SMALL 2018; 14:e1802025. [PMID: 30085392 DOI: 10.1002/smll.201802025] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 06/24/2018] [Indexed: 05/12/2023]
Affiliation(s)
- Yujie Ke
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
| | - Shancheng Wang
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
| | - Guowei Liu
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
| | - Ming Li
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
- Key Laboratory of Materials Physics; Anhui Key Laboratory of Nanomaterials and Nanotechnology; Institute of Solid State Physics; Chinese Academy of Sciences; Hefei 230031 P. R. China
| | - Timothy J. White
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
| | - Yi Long
- School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE); Nanomaterials for Energy and Energy-Water Nexus (NEW); Campus for Research Excellence and Technological Enterprise (CREATE); 1 Create Way Singapore 138602 Singapore
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17
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Sharma Y, Balachandran J, Sohn C, Krogel JT, Ganesh P, Collins L, Ievlev AV, Li Q, Gao X, Balke N, Ovchinnikova OS, Kalinin SV, Heinonen O, Lee HN. Nanoscale Control of Oxygen Defects and Metal-Insulator Transition in Epitaxial Vanadium Dioxides. ACS NANO 2018; 12:7159-7166. [PMID: 29906092 DOI: 10.1021/acsnano.8b03031] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Strongly correlated vanadium dioxide (VO2) is one of the most promising materials that exhibits a temperature-driven, metal-insulator transition (MIT) near room temperature. The ability to manipulate the MIT at nanoscale offers both insight into understanding the energetics of phase transition and a promising potential for nanoelectronic devices. In this work, we study nanoscale electrochemical modifications of the MIT in epitaxial VO2 thin films using a combined approach with scanning probe microscopy (SPM) and theoretical calculations. We find that applying electric voltages of different polarity through an SPM tip locally changes the contact potential difference and conductivity on the surface of VO2 by modulating the oxygen stoichiometry. We observed nearly 2 orders of magnitude change in resistance between positive and negative biased-tip written areas of the film, demonstrating the electric field modulated MIT behavior at the nanoscale. Density functional theory calculations, benchmarked against more accurate many-body quantum Monte Carlo calculations, provide information on the formation energetics of oxygen defects that can be further manipulated by strain. This study highlights the crucial role of oxygen vacancies in controlling the MIT in epitaxial VO2 thin films, useful for developing advanced electronic and iontronic devices.
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Affiliation(s)
- Yogesh Sharma
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Janakiraman Balachandran
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Changhee Sohn
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Jaron T Krogel
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Liam Collins
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Anton V Ievlev
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Qian Li
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Xiang Gao
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Nina Balke
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Olga S Ovchinnikova
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Olle Heinonen
- Materials Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Ho Nyung Lee
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
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18
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Tian Z, Xu B, Hsu B, Stan L, Yang Z, Mei Y. Reconfigurable Vanadium Dioxide Nanomembranes and Microtubes with Controllable Phase Transition Temperatures. NANO LETTERS 2018; 18:3017-3023. [PMID: 29633849 DOI: 10.1021/acs.nanolett.8b00483] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two additional structural forms, free-standing nanomembranes and microtubes, are reported and added to the vanadium dioxide (VO2) material family. Free-standing VO2 nanomembranes were fabricated by precisely thinning as-grown VO2 thin films and etching away the sacrificial layer underneath. VO2 microtubes with a range of controllable diameters were rolled-up from the VO2 nanomembranes. When a VO2 nanomembrane is rolled-up into a microtubular structure, a significant compressive strain is generated and accommodated therein, which decreases the phase transition temperature of the VO2 material. The magnitude of the compressive strain is determined by the curvature of the VO2 microtube, which can be rationally and accurately designed by controlling the tube diameter during the rolling-up fabrication process. The VO2 microtube rolling-up process presents a novel way to controllably tune the phase transition temperature of VO2 materials over a wide range toward practical applications. Furthermore, the rolling-up process is reversible. A VO2 microtube can be transformed back into a nanomembrane by introducing an external strain. Because of its tunable phase transition temperature and reversible shape transformation, the VO2 nanomembrane-microtube structure is promising for device applications. As an example application, a tubular microactuator device with low driving energy but large displacement is demonstrated at various triggering temperatures.
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Affiliation(s)
- Ziao Tian
- Department of Materials Science, State Key Laboratory of ASIC and Systems , Fudan University , 200433 Shanghai , PR China
| | - Borui Xu
- Department of Materials Science, State Key Laboratory of ASIC and Systems , Fudan University , 200433 Shanghai , PR China
| | - Bo Hsu
- Department of Electrical and Computer Engineering , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
| | - Liliana Stan
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Zheng Yang
- Department of Electrical and Computer Engineering , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
| | - YongFeng Mei
- Department of Materials Science, State Key Laboratory of ASIC and Systems , Fudan University , 200433 Shanghai , PR China
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19
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Mihailescu CN, Symeou E, Svoukis E, Negrea RF, Ghica C, Teodorescu V, Tanase LC, Negrila C, Giapintzakis J. Ambiguous Role of Growth-Induced Defects on the Semiconductor-to-Metal Characteristics in Epitaxial VO 2/TiO 2 Thin Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14132-14144. [PMID: 29595950 DOI: 10.1021/acsami.8b01436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling the semiconductor-to-metal transition temperature in epitaxial VO2 thin films remains an unresolved question both at the fundamental as well as the application level. Within the scope of this work, the effects of growth temperature on the structure, chemical composition, interface coherency and electrical characteristics of rutile VO2 epitaxial thin films grown on TiO2 substrates are investigated. It is hereby deduced that the transition temperature is lower than the bulk value of 340 K. However, it is found to approach this value as a function of increased growth temperature even though it is accompanied by a contraction along the V4+-V4+ bond direction, the crystallographic c-axis lattice parameter. Additionally, it is demonstrated that films grown at low substrate temperatures exhibit a relaxed state and a strongly reduced transition temperature. It is suggested that, besides thermal and epitaxial strain, growth-induced defects may strongly affect the electronic phase transition. The results of this work reveal the difficulty in extracting the intrinsic material response to strain, when the exact contribution of all strain sources cannot be effectively determined. The findings also bear implications on the limitations in obtaining the recently predicted novel semi-Dirac point phase in VO2/TiO2 multilayer structures.
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Affiliation(s)
- Cristian N Mihailescu
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
- National Institute for Laser , Plasma and Radiation Physics , 409 Atomistilor Street , PO Box MG-36, 077125 Magurele , Romania
| | - Elli Symeou
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
| | - Efthymios Svoukis
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
| | - Raluca F Negrea
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - Corneliu Ghica
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | | | - Liviu C Tanase
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - Catalin Negrila
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - John Giapintzakis
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
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20
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Umar ZA, Ahmed N, Ahmed R, Arshad M, Anwar-Ul-Haq M, Hussain T, Baig MA. Substrate temperature effects on the structural, compositional, and electrical properties of VO2
thin films deposited by pulsed laser deposition. SURF INTERFACE ANAL 2017. [DOI: 10.1002/sia.6368] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Z. A. Umar
- National Centre for Physics; Quaid-i-Azam University Campus; 54320 Islamabad Pakistan
| | - N. Ahmed
- National Centre for Physics; Quaid-i-Azam University Campus; 54320 Islamabad Pakistan
- Department of Physics; University of AJK; Muzaffarabad Pakisatan
| | - R. Ahmed
- National Centre for Physics; Quaid-i-Azam University Campus; 54320 Islamabad Pakistan
| | - M. Arshad
- National Centre for Physics; Quaid-i-Azam University Campus; 54320 Islamabad Pakistan
| | - M. Anwar-Ul-Haq
- Department of Physics; University of Sargodha; Sargodha Pakistan
| | - T. Hussain
- Centre for Advanced Studies in Physics (CASP); GC University; 54000 Lahore Pakistan
| | - M. A. Baig
- National Centre for Physics; Quaid-i-Azam University Campus; 54320 Islamabad Pakistan
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21
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Li X, Schaak RE. Size‐ and Interface‐Modulated Metal–Insulator Transition in Solution‐Synthesized Nanoscale VO
2
‐TiO
2
‐VO
2
Heterostructures. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201706599] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Xuefei Li
- Department of Chemistry and Materials Research Institute The Pennsylvania State University University Park PA 16802 USA
| | - Raymond E. Schaak
- Department of Chemistry and Materials Research Institute The Pennsylvania State University University Park PA 16802 USA
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22
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Li X, Schaak RE. Size‐ and Interface‐Modulated Metal–Insulator Transition in Solution‐Synthesized Nanoscale VO
2
‐TiO
2
‐VO
2
Heterostructures. Angew Chem Int Ed Engl 2017; 56:15550-15554. [DOI: 10.1002/anie.201706599] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/15/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Xuefei Li
- Department of Chemistry and Materials Research Institute The Pennsylvania State University University Park PA 16802 USA
| | - Raymond E. Schaak
- Department of Chemistry and Materials Research Institute The Pennsylvania State University University Park PA 16802 USA
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23
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Sakai J, Katano S, Kuwahara M, Uehara Y. Pump-probe STM light emission spectroscopy for detection of photo-induced semiconductor-metal phase transition of VO 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:405001. [PMID: 28703712 DOI: 10.1088/1361-648x/aa7f93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We attempted to observe pump-probe scanning tunneling microscopy (STM)-light emission (LE) from a VO2 thin film grown on a rutile TiO2(0 0 1) substrate, with an Ag tip fixed over a semiconducting domain. Laser pulses from a Ti:sapphire laser (wavelength 920 nm; pulse width less than 1.5 ps) irradiated the tip-sample gap as pump and probe light sources. With a photon energy of 2.7 eV, suggesting phase transition from semiconducting monoclinic (M) to metallic rutile (R) phases in relation to the electronic band structure, faint LE was observed roughly 30 ps after the irradiation of the pump pulse, followed by retention for roughly 20 ps. The incident energy fluence of the pump pulse at the gap was five orders of magnitude lower than the threshold value for reported photo-induced M-R phase transition. The mechanism that makes it possible to reduce the threshold fluence is discussed.
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Affiliation(s)
- Joe Sakai
- GREMAN, UMR 7347 CNRS/Université François Rabelais de Tours, 37200 Tours, France
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24
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Photoinduced Strain Release and Phase Transition Dynamics of Solid-Supported Ultrathin Vanadium Dioxide. Sci Rep 2017; 7:10045. [PMID: 28855670 PMCID: PMC5577108 DOI: 10.1038/s41598-017-10217-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/04/2017] [Indexed: 11/22/2022] Open
Abstract
The complex phase transitions of vanadium dioxide (VO2) have drawn continual attention for more than five decades. Dynamically, ultrafast electron diffraction (UED) with atomic-scale spatiotemporal resolution has been employed to study the reaction pathway in the photoinduced transition of VO2, using bulk and strain-free specimens. Here, we report the UED results from 10-nm-thick crystalline VO2 supported on Al2O3(0001) and examine the influence of surface stress on the photoinduced structural transformation. An ultrafast release of the compressive strain along the surface-normal direction is observed at early times following the photoexcitation, accompanied by faster motions of vanadium dimers that are more complex than simple dilation or bond tilting. Diffraction simulations indicate that the reaction intermediate involved on picosecond times may not be a single state, which implies non-concerted atomic motions on a multidimensional energy landscape. At longer times, a laser fluence multiple times higher than the thermodynamic enthalpy threshold is required for complete conversion from the initial monoclinic structure to the tetragonal lattice. For certain crystalline domains, the structural transformation is not seen even on nanosecond times following an intense photoexcitation. These results signify a time-dependent energy distribution among various degrees of freedom and reveal the nature of and the impact of strain on the photoinduced transition of VO2.
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25
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Sohn JI, Cha SN, Son SB, Kim JM, Welland ME, Hong WK. Metastable state-induced consecutive step-like negative differential resistance behaviors in single crystalline VO 2 nanobeams. NANOSCALE 2017; 9:8200-8206. [PMID: 28580984 DOI: 10.1039/c7nr00318h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate the current-dependent consecutive appearance of two different negative differential resistance (NDR) transitions in a single crystalline VO2 nanobeam epitaxially grown on a c-cut sapphire substrate. It is revealed that the first NDR occurs at an approximately constant current level as a result of the carrier injection-induced transition, independent of a thermally induced phase transition. In contrast, it is observed that the second NDR exhibits a temperature-dependent behavior and current values triggering the metal-insulator transition (MIT) are strongly mediated by Joule heating effects in a phase coexisting temperature range. Moreover, we find that the electrically and thermally triggered MIT behavior can be closely related with the alternate occurrence of current-induced multiple insulating and metallic phase coexistence in the nanobeam. These findings indicate that the current density passing through VO2 plays a critical role in both the electrical and structural phase transitions.
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Affiliation(s)
- Jung Inn Sohn
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK.
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26
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Torres D, Zhang J, Dooley S, Tan X, Sepúlveda N. Modeling of MEMS Mirrors Actuated by Phase-Change Mechanism. MICROMACHINES 2017. [PMCID: PMC6189919 DOI: 10.3390/mi8050138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- David Torres
- Department of Electrical & Computer Engineering, Michigan State University, East Lansing, MI 48840, USA; (D.T.); (X.T.)
| | - Jun Zhang
- Department of Electrical & Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA;
| | - Sarah Dooley
- Air Force Research Laboratory, Sensors Directorate, WP-AFB, Dayton, OH 45433, USA;
| | - Xiaobo Tan
- Department of Electrical & Computer Engineering, Michigan State University, East Lansing, MI 48840, USA; (D.T.); (X.T.)
| | - Nelson Sepúlveda
- Department of Electrical & Computer Engineering, Michigan State University, East Lansing, MI 48840, USA; (D.T.); (X.T.)
- Correspondence: ; Tel.: +1-517-432-2130
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27
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Liu M, Sternbach AJ, Basov DN. Nanoscale electrodynamics of strongly correlated quantum materials. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:014501. [PMID: 27811387 DOI: 10.1088/0034-4885/80/1/014501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.
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Affiliation(s)
- Mengkun Liu
- Department of Physics, Stony Brook University, Stony Brook, NY 11794, USA
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28
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Kasırga TS, Coy JM, Park JH, Cobden DH. Visualization of one-dimensional diffusion and spontaneous segregation of hydrogen in single crystals of VO2. NANOTECHNOLOGY 2016; 27:345708. [PMID: 27454751 DOI: 10.1088/0957-4484/27/34/345708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogen intercalation in solids is common, complicated, and very difficult to monitor. In a new approach to the problem, we have studied the profile of hydrogen diffusion in single-crystal nanobeams and plates of VO2, exploiting the fact that hydrogen doping in this material leads to visible darkening near room temperature connected with the metal-insulator transition at 65 °C. We observe hydrogen diffusion along the rutile c-axis but not perpendicular to it, making this a highly one-dimensional diffusion system. We obtain an activated diffusion coefficient, [Formula: see text] applicable in metallic phase. In addition, we observe dramatic supercooling of the hydrogen-induced metallic phase and spontaneous segregation of the hydrogen into stripes implying that the diffusion process is highly nonlinear, even in the absence of defects. Similar complications may occur in hydrogen motion in other materials but are not revealed by conventional measurement techniques.
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Affiliation(s)
- T Serkan Kasırga
- Department of Physics, University of Washington, Seattle, WA 98195, USA. UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey
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29
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Kim MW, Ha SS, Seo O, Noh DY, Kim BJ. Real-Time Structural and Electrical Characterization of Metal-Insulator Transition in Strain-Modulated Single-Phase VO2 Wires with Controlled Diameters. NANO LETTERS 2016; 16:4074-4081. [PMID: 27253750 DOI: 10.1021/acs.nanolett.6b00719] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Single-crystal VO2 wires have gained tremendous popularity for enabling the study of the fundamental properties of the metal-insulator transition (MIT); however, it remains tricky to precisely measure the intrinsic properties of the transitional phases with controlled wire-growth properties, such as diameter. Here, we report a facile method for growing VO2 wires with controlled diameters by separating the formation of the liquidus V2O5 seed droplets from the evolution of the VO2 wire using oxygen gas. The kinetic analyses suggest that the growth proceeds via the VS (vapor-solid) mechanism, whereas the droplet determines the size and the location of the wire. In situ Raman spectroscopy combined with analyses of the electrical properties of an individual wire allowed us to construct a diameter-temperature phase diagram from three initial phases (i.e., M1, T, and M2), which were created by misfit stress from the substrate and were preserved at room temperature. We also correlated this relation with resistivity-diameter and activation energy-diameter relations supported by theoretical modeling. These carefully designed approaches enabled us to elucidate the details of the phase transitions over a wide range of stress conditions, offering an opportunity to quantify relevant thermodynamic and electronic parameters (including resistivities, activation energies, and energy barriers of the key insulating phases) and to explain the intriguing behaviors of the T phase during the MIT.
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Affiliation(s)
- Min-Woo Kim
- School of Materials Science and Engineering and ‡Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Sung-Soo Ha
- School of Materials Science and Engineering and ‡Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Okkyun Seo
- School of Materials Science and Engineering and ‡Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Do Young Noh
- School of Materials Science and Engineering and ‡Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
| | - Bong-Joong Kim
- School of Materials Science and Engineering and ‡Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST) , 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, South Korea
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Yoon J, Kim H, Chen X, Tamura N, Mun BS, Park C, Ju H. Controlling the Temperature and Speed of the Phase Transition of VO2 Microcrystals. ACS APPLIED MATERIALS & INTERFACES 2016; 8:2280-2286. [PMID: 26713678 DOI: 10.1021/acsami.5b11144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigated the control of two important parameters of vanadium dioxide (VO2) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ∼70 to ∼1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition by using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10(2) to 1.7 × 10(4) μm/s as the width decreases from ∼50 to ∼2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO2, the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO2 microcrystals. Our findings not only enhance the understanding of VO2 intrinsic properties but also contribute to the development of innovative electronic devices.
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Affiliation(s)
- Joonseok Yoon
- Department of Physics, Yonsei University , Seoul 03722, Republic of Korea
| | - Howon Kim
- Department of Physics, Yonsei University , Seoul 03722, Republic of Korea
| | - Xian Chen
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology , Hong Kong 999077, China
| | - Nobumichi Tamura
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | | | - Changwoo Park
- Division of Applied Chemistry and Biotechnology, Hanbat National University , Daejeon 34158, Republic of Korea
- Advanced Nano Products , Sejong, 30077, Republic of Korea
| | - Honglyoul Ju
- Department of Physics, Yonsei University , Seoul 03722, Republic of Korea
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31
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Chen L, Cui Y, Shi S, Liu B, Luo H, Gao Y. First-principles study of the effect of oxygen vacancy and strain on the phase transition temperature of VO2. RSC Adv 2016. [DOI: 10.1039/c6ra19121e] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The calculated oxygen-vacancy diffusion barrier indicates that the existence of oxygen-vacancy could stabilize the rutile phase at a low temperature.
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Affiliation(s)
- Lanli Chen
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Yuanyuan Cui
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Siqi Shi
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Bin Liu
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Hongjie Luo
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Yanfeng Gao
- School of Materials Science and Engineering
- Shanghai University
- Shanghai 200444
- China
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32
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Asayesh-Ardakani H, Nie A, Marley PM, Zhu Y, Phillips PJ, Singh S, Mashayek F, Sambandamurthy G, Low KB, Klie RF, Banerjee S, Odegard GM, Shahbazian-Yassar R. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO2 Nanowires. NANO LETTERS 2015; 15:7179-7188. [PMID: 26457771 DOI: 10.1021/acs.nanolett.5b03219] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO2) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO2 are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WxV1-xO2 nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122̅) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO2 structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.
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Affiliation(s)
- Hasti Asayesh-Ardakani
- Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49933-1295, United States
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Anmin Nie
- Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49933-1295, United States
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Peter M Marley
- Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States
| | - Yihan Zhu
- Advanced Membranes and Porous Materials Center, King Abdullah University of Science & Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Patrick J Phillips
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Sujay Singh
- Department of Physics, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States
| | - Farzad Mashayek
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Ganapathy Sambandamurthy
- Department of Physics, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States
| | - Ke-Bin Low
- Research Resource Center, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Robert F Klie
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
| | - Sarbajit Banerjee
- Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States
| | | | - Reza Shahbazian-Yassar
- Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49933-1295, United States
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago , Chicago, Illinois 60607-7059, United States
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33
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Quackenbush NF, Paik H, Woicik JC, Arena DA, Schlom DG, Piper LFJ. X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2. MATERIALS 2015; 8:5452-5466. [PMID: 28793516 PMCID: PMC5455529 DOI: 10.3390/ma8085255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 11/23/2022]
Abstract
Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.
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Affiliation(s)
- Nicholas F Quackenbush
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
| | - Hanjong Paik
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
| | - Joseph C Woicik
- Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Dario A Arena
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA.
| | - Louis F J Piper
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
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Substrate-mediated strain effect on the role of thermal heating and electric field on metal-insulator transition in vanadium dioxide nanobeams. Sci Rep 2015; 5:10861. [PMID: 26040637 PMCID: PMC4455114 DOI: 10.1038/srep10861] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/01/2015] [Indexed: 12/05/2022] Open
Abstract
Single-crystalline vanadium dioxide (VO2) nanostructures have recently attracted great attention because of their single domain metal-insulator transition (MIT) nature that differs from a bulk sample. The VO2 nanostructures can also provide new opportunities to explore, understand, and ultimately engineer MIT properties for applications of novel functional devices. Importantly, the MIT properties of the VO2 nanostructures are significantly affected by stoichiometry, doping, size effect, defects, and in particular, strain. Here, we report the effect of substrate-mediated strain on the correlative role of thermal heating and electric field on the MIT in the VO2 nanobeams by altering the strength of the substrate attachment. Our study may provide helpful information on controlling the properties of VO2 nanobeam for the device applications by changing temperature and voltage with a properly engineered strain.
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35
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Inhomogeneity of the ultrafast insulator-to-metal transition dynamics of VO2. Nat Commun 2015; 6:6849. [DOI: 10.1038/ncomms7849] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 03/05/2015] [Indexed: 11/09/2022] Open
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36
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Hongwei L, Junpeng L, Minrui Z, Hai TS, Haur SC, Xinhai Z, Lin K. Size effects on metal-insulator phase transition in individual vanadium dioxide nanowires. OPTICS EXPRESS 2014; 22:30748-30755. [PMID: 25607023 DOI: 10.1364/oe.22.030748] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the size effects on the metal-insulator phase transition of vanadium dioxide (VO2) nanowires prepared by chemical vapor deposition. The phase transition temperature can be tuned from 67 °C in the bulk VO2 to as low as 29°C by reducing the diameter of VO2 nanowires to nanoscale. Temperature-dependent Raman spectra display a clear dynamic picture on the metal-insulator phase transition process of the VO2 nanowires. Whilst, Raman study shows no remarkable strain effect on the phase transition behaviors of our samples. The increasing surface defect density with reducing nanowire size facilitates the decreasing phase transition temperature. In addition, the polarized-photocurrent effect was observed, resulting from the anisotropy of the photoresponse and also caused by the reduced dimensionality.Our results indicate that size of VO2 nanostructures can dominate their thermoelectric and photoelectrical properties.
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37
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Horrocks GA, Singh S, Likely MF, Sambandamurthy G, Banerjee S. Scalable hydrothermal synthesis of free-standing VO₂ nanowires in the M1 phase. ACS APPLIED MATERIALS & INTERFACES 2014; 6:15726-15732. [PMID: 25153653 DOI: 10.1021/am504372t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
VO2 nanostructures derived from solution-phase methods are often plagued by broadened and relatively diminished metal-insulator transitions and adventitious doping due to imperfect control of stoichiometry. Here, we demonstrate a stepwise scalable hydrothermal and annealing route for obtaining VO2 nanowires exhibiting almost 4 orders of magnitude abrupt (within 1 °C) metal-insulator transitions. The prepared nanowires have been characterized across their structural and electronic phase transitions using single-nanowire Raman microprobe analysis, ensemble differential scanning calorimetry, and single-nanowire electrical transport measurements. The electrical band gap is determined to be 600 meV and is consistent with the optical band gap of VO2, and the narrowness of differential scanning calorimetry profiles indicates homogeneity of stoichiometry. The preparation of high-quality free-standing nanowires exhibiting pronounced metal-insulator transitions by a solution-phase process allows for scalability, further solution-phase processing, incorporation within nanocomposites, and integration onto arbitrary substrates.
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Affiliation(s)
- Gregory A Horrocks
- Department of Chemistry, Texas A&M University , College Station, Texas 77842-3012, United States
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38
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Bahlawane N, Lenoble D. Vanadium Oxide Compounds:Structure, Properties, and Growth from the Gas Phase. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/cvde.201400057] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Naoufal Bahlawane
- Nanomaterials Research Unit, SAM Department; Centre de Recherche Public - Gabriel Lippmann; 41, rue du Brill 4422 Belvaux (Luxembourg)
| | - Damien Lenoble
- Nanomaterials Research Unit, SAM Department; Centre de Recherche Public - Gabriel Lippmann; 41, rue du Brill 4422 Belvaux (Luxembourg)
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39
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Lu J, Liu H, Deng S, Zheng M, Wang Y, van Kan JA, Tang SH, Zhang X, Sow CH, Mhaisalkar SG. Highly sensitive and multispectral responsive phototransistor using tungsten-doped VO2 nanowires. NANOSCALE 2014; 6:7619-7627. [PMID: 24896423 DOI: 10.1039/c4nr00898g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this work, we report a novel and feasible strategy for the practical applications of one-dimensional ultrasensitive phototransistors made of tungsten-doped VO2 single nanowires. The photoconductive response of the single nanowire device was investigated under different visible light excitations (405 nm, 532 nm, and 660 nm). The phototransistor device exhibited ultrafast photoresponse, high responsivity, broad multispectral response, and rapid saturation characteristic curves. These promising results help to promote the applications of this material in nano-scale optoelectronic devices such as efficient multispectral phototransistors and optical switches.
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Affiliation(s)
- Junpeng Lu
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore.
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40
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Wu Y, Fan L, Huang W, Chen S, Chen S, Chen F, Zou C, Wu Z. Depressed transition temperature of WxV1−xO2: mechanistic insights from the X-ray absorption fine structure (XAFS) spectroscopy. Phys Chem Chem Phys 2014; 16:17705-14. [DOI: 10.1039/c4cp01661k] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Favaloro T, Suh J, Vermeersch B, Liu K, Gu Y, Chen LQ, Wang KX, Wu J, Shakouri A. Direct observation of nanoscale Peltier and Joule effects at metal-insulator domain walls in vanadium dioxide nanobeams. NANO LETTERS 2014; 14:2394-2400. [PMID: 24735496 DOI: 10.1021/nl500042x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The metal to insulator transition (MIT) of strongly correlated materials is subject to strong lattice coupling, which brings about the unique one-dimensional alignment of metal-insulator (M-I) domains along nanowires or nanobeams. Many studies have investigated the effects of stress on the MIT and hence the phase boundary, but few have directly examined the temperature profile across the metal-insulating interface. Here, we use thermoreflectance microscopy to create two-dimensional temperature maps of single-crystalline VO2 nanobeams under external bias in the phase coexisting regime. We directly observe highly localized alternating Peltier heating and cooling as well as Joule heating concentrated at the M-I domain boundaries, indicating the significance of the domain walls and band offsets. Utilizing the thermoreflectance technique, we are able to elucidate strain accumulation along the nanobeam and distinguish between two insulating phases of VO2 through detection of the opposite polarity of their respective thermoreflectance coefficients. Microelasticity theory was employed to predict favorable domain wall configurations, confirming the monoclinic phase identification.
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Affiliation(s)
- Tela Favaloro
- Baskin School of Engineering, University of California , Santa Cruz, California 95064, United States
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42
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Role of microstructures on the M1-M2 phase transition in epitaxial VO2 thin films. Sci Rep 2014; 4:4854. [PMID: 24798056 PMCID: PMC4010922 DOI: 10.1038/srep04854] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 04/14/2014] [Indexed: 11/09/2022] Open
Abstract
Vanadium dioxide (VO2) with its unique sharp resistivity change at the metal-insulator transition (MIT) has been extensively considered for the near-future terahertz/infrared devices and energy harvesting systems. Controlling the epitaxial quality and microstructures of vanadium dioxide thin films and understanding the metal-insulator transition behaviors are therefore critical to novel device development. The metal-insulator transition behaviors of the epitaxial vanadium dioxide thin films deposited on Al2O3 (0001) substrates were systematically studied by characterizing the temperature dependency of both Raman spectrum and Fourier transform infrared spectroscopy. Our findings on the correlation between the nucleation dynamics of intermediate monoclinic (M2) phase with microstructures will open a new avenue for the design and integration of advanced heterostructures with controllable multifunctionalities for sensing and imaging system applications.
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43
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Lu P, Zhou J, Liu X, Zhang Z, Xu F, Zhang L, Mou X, Feng J, Gao Y, Zhao J. Characterization of phase-transition-induced micro-domain structures in vanadium dioxide. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714002854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The displacive structural phase transition of vanadium dioxide (VO2) from the high-temperature tetragonal rutile (R) phase to the low-temperature monoclinic M1 or M2 phase may induce the formation of a variety of domain structures. Here, all possible types of phase-transition-induced domain structures of the M1 and M2 phases have been theoretically formulated by using a general space group method. The predicted domain structures of the M1 phase, including mirror or rotation twins and antiphase domains, have been confirmed by transmission electron microscopy observation of VO2powders and films, while the antiphase domains have never been involved in previous studies. The changes undergone by domain structures during a thermal or electron-beam-induced phase transition have been investigated. These results may suggest the potential influence of domain structures on the nucleation and progress of phase transitions, which unambiguously affect the hysteresis behavior of the first-order transition of VO2.
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Holsteen A, Kim IS, Lauhon LJ. Extraordinary dynamic mechanical response of vanadium dioxide nanowires around the insulator to metal phase transition. NANO LETTERS 2014; 14:1898-1902. [PMID: 24597551 DOI: 10.1021/nl404678k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Nanomechanical resonators provide a compelling platform to investigate and exploit phase transitions coupled to mechanical degrees of freedom because resonator frequencies and quality factors are exquisitely sensitive to changes in state, particularly for discontinuous changes accompanying a first-order phase transition. Correlated scanning fiber-optic interferometry and dual-beam Raman spectroscopy were used to investigate mechanical fluctuations of vanadium dioxide (VO2) nanowires across the first order insulator to metal transition. Unusually large and controllable changes in resonator frequency were observed due to the influences of domain wall motion and anomalous phonon softening on the effective modulus. In addition, extraordinary static and dynamic displacements were generated by local strain gradients, suggesting new classes of sensors and nanoelectromechanical devices with programmable discrete outputs as a function of continuous inputs.
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Affiliation(s)
- Aaron Holsteen
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
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45
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Manca N, Pellegrino L, Kanki T, Yamasaki S, Tanaka H, Siri AS, Marré D. Programmable mechanical resonances in MEMS by localized joule heating of phase change materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:6430-6435. [PMID: 24038351 DOI: 10.1002/adma.201302087] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/05/2013] [Indexed: 06/02/2023]
Abstract
A programmable micromechanical resonator based on a VO2 thin film is reported. Multiple mechanical eigenfrequency states are programmed using Joule heating as local power source, gradually driving the phase transition of VO2 around its Metal-Insulator transition temperature. Phase coexistence of domains is used to tune the stiffness of the device via local control of internal stresses and mechanical properties. This study opens perspectives for developing mechanically configurable nanostructure arrays.
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Affiliation(s)
- Nicola Manca
- CNR-SPIN, Corso Perrone 24, Genova, 16152, Italy; Physics Department, University of Genova, Via Dodecaneso 33, Genova, 16146, Italy
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46
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Peng WW, Niu G, Tétot R, Vilquin B, Raimondi F, Brubach JB, Amzallag E, Yanagida T, Autier-Laurent S, Lecoeur P, Roy P. Insulator-metal transition of VO₂ ultrathin films on silicon: evidence for an electronic origin by infrared spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:445402. [PMID: 24121423 DOI: 10.1088/0953-8984/25/44/445402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report on the first simultaneous observations of both electronic and structural temperature-induced insulator-to-metal transition (IMT) in VO2 ultrathin films, made possible by the use of broad range transmission infrared spectroscopy. Thanks to these techniques, the infrared phonon structures, as well as the appearance of the free carrier signature, were resolved for the first time. The temperature-resolved spectra allowed the determination of the temperature hysteresis for both the structural (monoclinic-to-rutile) and electronic (insulator-to-metallic) transitions. The combination of these new observations and DFT simulations for the monoclinic structure allows us to verify the direct transition from monoclinic (M1) to rutile and exclude an intermediate structural monoclinic form (M2). The delay in structural modification compared to the primer electronic transition (325 K compared to 304 K) supports the role of free charges as the transition driving force. The shape of the free charge hysteresis suggests that the primer electronic transition occurs first at 304 K, followed by both its propagation to the heart of the layer and the structural transition when T increases. This study outlines further the potential of VO2 ultrathin films integrated on silicon for optoelectronics and microelectronics.
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Affiliation(s)
- W W Peng
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette, France
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47
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Park JH, Coy JM, Kasirga TS, Huang C, Fei Z, Hunter S, Cobden DH. Measurement of a solid-state triple point at the metal-insulator transition in VO2. Nature 2013; 500:431-4. [PMID: 23969461 DOI: 10.1038/nature12425] [Citation(s) in RCA: 335] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/24/2013] [Indexed: 11/09/2022]
Abstract
First-order phase transitions in solids are notoriously challenging to study. The combination of change in unit cell shape, long range of elastic distortion and flow of latent heat leads to large energy barriers resulting in domain structure, hysteresis and cracking. The situation is worse near a triple point, where more than two phases are involved. The well-known metal-insulator transition in vanadium dioxide, a popular candidate for ultrafast optical and electrical switching applications, is a case in point. Even though VO2 is one of the simplest strongly correlated materials, experimental difficulties posed by the first-order nature of the metal-insulator transition as well as the involvement of at least two competing insulating phases have led to persistent controversy about its nature. Here we show that studying single-crystal VO2 nanobeams in a purpose-built nanomechanical strain apparatus allows investigation of this prototypical phase transition with unprecedented control and precision. Our results include the striking finding that the triple point of the metallic phase and two insulating phases is at the transition temperature, Ttr = Tc, which we determine to be 65.0 ± 0.1 °C. The findings have profound implications for the mechanism of the metal-insulator transition in VO2, but they also demonstrate the importance of this approach for mastering phase transitions in many other strongly correlated materials, such as manganites and iron-based superconductors.
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Affiliation(s)
- Jae Hyung Park
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
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48
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Li Y, Ji S, Gao Y, Luo H, Kanehira M. Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings. Sci Rep 2013; 3:1370. [PMID: 23546301 PMCID: PMC3613806 DOI: 10.1038/srep01370] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 01/17/2013] [Indexed: 11/10/2022] Open
Abstract
Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating.
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Affiliation(s)
- Yamei Li
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai institute of Ceramics, Chinese Academy of Sciences, Dingxi 1295, Changning, Shanghai, 200050, China
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Quackenbush NF, Tashman JW, Mundy JA, Sallis S, Paik H, Misra R, Moyer JA, Guo JH, Fischer DA, Woicik JC, Muller DA, Schlom DG, Piper LFJ. Nature of the metal insulator transition in ultrathin epitaxial vanadium dioxide. NANO LETTERS 2013; 13:4857-4861. [PMID: 24000961 DOI: 10.1021/nl402716d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have combined hard X-ray photoelectron spectroscopy with angular dependent O K-edge and V L-edge X-ray absorption spectroscopy to study the electronic structure of metallic and insulating end point phases in 4.1 nm thick (14 units cells along the c-axis of VO2) films on TiO2(001) substrates, each displaying an abrupt MIT centered at ~300 K with width <20 K and a resistance change of ΔR/R > 10(3). The dimensions, quality of the films, and stoichiometry were confirmed by a combination of scanning transmission electron microscopy with electron energy loss spectroscopy, X-ray spectroscopy, and resistivity measurements. The measured end point phases agree with their bulk counterparts. This clearly shows that, apart from the strain induced change in transition temperature, the underlying mechanism of the MIT for technologically relevant dimensions must be the same as the bulk for this orientation.
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Affiliation(s)
- N F Quackenbush
- Department of Physics, Applied Physics and Astronomy, Binghamton University , Binghamton, New York 13902, United States
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Parikh P, Chakraborty C, Abhilash TS, Sengupta S, Cheng C, Wu J, Deshmukh MM. Dynamically tracking the strain across the metal-insulator transition in VO2 measured using electromechanical resonators. NANO LETTERS 2013; 13:4685-4689. [PMID: 24000932 DOI: 10.1021/nl402116f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We study the strain state of doubly clamped VO2 nanobeam devices by dynamically probing resonant frequency of the nanoscale electromechanical device across the metal-insulator transition. Simultaneous resistance and resonance measurements indicate M1-M2 phase transition in the insulating state with a drop in resonant frequency concomitant with an increase in resistance. The resonant frequency increases by ~7 MHz with the growth of metallic domain (M2-R transition) due to the development of tensile strain in the nanobeam. Our approach to dynamically track strain coupled with simultaneous resistance and resonance measurements using electromechanical resonators enables the study of lattice-involved interactions more precisely than static strain measurements. This technique can be extended to other phase change systems important for device applications.
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Affiliation(s)
- Pritesh Parikh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research , Mumbai 400005, India
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