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Chen Y, Huang Y, Zeng J, Kang Y, Tan Y, Xie X, Wei B, Li C, Fang L, Jiang T. Energy-Efficient ReS 2-Based Optoelectronic Synapse for 3D Object Reconstruction and Recognition. ACS Appl Mater Interfaces 2023; 15:58631-58642. [PMID: 38054897 DOI: 10.1021/acsami.3c14958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
The neuromorphic vision system (NVS) equipped with optoelectronic synapses integrates perception, storage, and processing and is expected to address the issues of traditional machine vision. However, owing to their lack of stereo vision, existing NVSs focus on 2D image processing, which makes it difficult to solve problems such as spatial cognition errors and low-precision interpretation. Consequently, inspired by the human visual system, an NVS with stereo vision is developed to achieve 3D object recognition, depending on the prepared ReS2 optoelectronic synapse with 12.12 fJ ultralow power consumption. This device exhibits excellent optical synaptic plasticity derived from the persistent photoconductivity effect. As the cornerstone for 3D vision, color planar information is successfully discriminated and stored in situ at the sensor end, benefiting from its wavelength-dependent plasticity in the visible region. Importantly, the dependence of the channel conductance on the target distance is experimentally revealed, implying that the structure information on the object can be directly captured and stored by the synapse. The 3D image of the object is successfully reconstructed via fusion of its planar and depth images. Therefore, the proposed 3D-NVS based on ReS2 synapses for 3D objects achieves a recognition accuracy of 97.0%, which is much higher than that for 2D objects (32.6%), demonstrating its strong ability to prevent 2D-photo spoofing in applications such as face payment, entrance guard systems, and others.
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Affiliation(s)
- Yabo Chen
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yujie Huang
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Junwei Zeng
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yan Kang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yinlong Tan
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Xiangnan Xie
- Institute of Quantum Information Science and Technology, College of Science, National University of Defense Technology, Changsha 410073, P. R. China
| | - Bo Wei
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Cheng Li
- Institute of Quantum Information Science and Technology, College of Science, National University of Defense Technology, Changsha 410073, P. R. China
| | - Liang Fang
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Tian Jiang
- Institute of Quantum Information Science and Technology, College of Science, National University of Defense Technology, Changsha 410073, P. R. China
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Kim HS, Park H, Cho WJ. Light-Stimulated IGZO Transistors with Tunable Synaptic Plasticity Based on Casein Electrolyte Electric Double Layer for Neuromorphic Systems. Biomimetics (Basel) 2023; 8:532. [PMID: 37999173 PMCID: PMC10669183 DOI: 10.3390/biomimetics8070532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
Abstract
In this study, optoelectronic synaptic transistors based on indium-gallium-zinc oxide (IGZO) with a casein electrolyte-based electric double layer (EDL) were examined. The casein electrolyte played a crucial role in modulating synaptic plasticity through an internal proton-induced EDL effect. Thus, important synaptic behaviors, such as excitatory post-synaptic current, paired-pulse facilitation, and spike rate-dependent and spike number-dependent plasticity, were successfully implemented by utilizing the persistent photoconductivity effect of the IGZO channel stimulated by light. The synergy between the light stimulation and the EDL effect allowed the effective modulation of synaptic plasticity, enabling the control of memory levels, including the conversion of short-term memory to long-term memory. Furthermore, a Modified National Institute of Standards and Technology digit recognition simulation was performed using a three-layer artificial neural network model, achieving a high recognition rate of 90.5%. These results demonstrated a high application potential of the proposed optoelectronic synaptic transistors in neuromorphic visual systems.
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Affiliation(s)
- Hwi-Su Kim
- Department of Electronic Materials Engineering, Kwangwoon University, Gwangun-ro 20, Nowon-gu, Seoul 01897, Republic of Korea;
| | - Hamin Park
- Department of Electronic Engineering, Kwangwoon University, Gwangun-ro 20, Nowon-gu, Seoul 01897, Republic of Korea;
| | - Won-Ju Cho
- Department of Electronic Materials Engineering, Kwangwoon University, Gwangun-ro 20, Nowon-gu, Seoul 01897, Republic of Korea;
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3
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Yang G, Kim Y, Jeon J, Lee M, Kim D, Kim S, Eom K, Lee H. Reversible Photomodulation of Two-Dimensional Electron Gas in LaAlO 3/SrTiO 3 Heterostructures. Nano Lett 2023. [PMID: 37418557 DOI: 10.1021/acs.nanolett.3c01076] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Long-lived photoinduced conductance changes in LaAlO3/SrTiO3 (LAO/STO) heterostructures enable their use in optoelectronic memory applications. However, it remains challenging to quench the persistent photoconductivity (PPC) instantly and reproducibly, which limits the reversible optoelectronic switching. Herein, we demonstrate a reversible photomodulation of two-dimensional electron gas (2DEG) in LAO/STO heterostructures with high reproducibility. By irradiating UV pulses, the 2DEG at the LAO/STO interface is gradually transformed to the PPC state. Notably, the PPC can be completely removed by water treatment when two key requirements are met: (1) the moderate oxygen deficiency in STO and (2) the minimal band edge fluctuation at the interface. Through our X-ray photoelectron spectroscopy and electrical noise analysis, we reveal that the reproducible change in the conductivity of 2DEG is directly attributed to the surface-driven electron relaxation in the STO. Our results provide a stepping-stone toward developing optically tunable memristive devices based on oxide 2DEG systems.
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Affiliation(s)
- Gyeongmo Yang
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Youngmin Kim
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Jaeyoung Jeon
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Minkyung Lee
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Doyeop Kim
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Sungkyu Kim
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Kitae Eom
- School of Advanced Materials science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Hyungwoo Lee
- Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
- Department of Physics, Ajou University, Suwon 16499, Republic of Korea
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4
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Yang H, Cheng TH, Xin Q, Liu Y, Feng HY, Luo F, Mu W, Jia Z, Tao X. Efficient Suppression of Persistent Photoconductivity in β-Ga 2O 3-Based Photodetectors with Square Nanopore Arrays. ACS Appl Mater Interfaces 2023. [PMID: 37368844 DOI: 10.1021/acsami.3c05265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
In this work, square nanopore arrays were developed on the surface of β-Ga2O3 microflakes using focused ion beam (FIB) etching, and solar-blind photodetectors (PDs) were fabricated based on the β-Ga2O3 microflakes with square nanopore arrays. The β-Ga2O3 microflake-based device was transformed from a gate voltage depletion mode to an oxygen depletion mode by FIB etching. The developed device exhibited excellent solar-blind PD performance with extremely high responsivity (1.8 × 105 at 10 V), detectivity (3.4 × 1018 Jones at 10 V), and light-to-dark ratio (9.3 × 108 at 5 V) as well as good repeatability and excellent stability. The intrinsic mechanism responsible for this performance was then systematically discussed. This work opens up a new avenue for the fabrication of high-performance β-Ga2O3-based low-dimensional PDs with high reproducibility by employing the FIB etching process.
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Affiliation(s)
- Huarong Yang
- School of Microelectronics, Shandong University, Ji'nan 250100, China
| | - Tong-Huai Cheng
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Qian Xin
- School of Microelectronics, Shandong University, Ji'nan 250100, China
| | - Yiyuan Liu
- State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Hua Yu Feng
- School of Microelectronics, Shandong University, Ji'nan 250100, China
| | - Feng Luo
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Wenxiang Mu
- State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Zhitai Jia
- State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
- Shandong Research Institute of Industrial Technology, Jinan 250100, Shandong, China
| | - Xutang Tao
- State Key Laboratory of Crystal Materials, Institute of Novel Semiconductors, Institute of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
- Shenzhen Research Institute of Shandong University, Shenzhen 518057, China
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5
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Hnatovsky C, Mihailov S, Hilke M, Pfeiffer L, West K, Studenikin S. An Optical Technique to Produce Embedded Quantum Structures in Semiconductors. Nanomaterials (Basel) 2023; 13:nano13101622. [PMID: 37242039 DOI: 10.3390/nano13101622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/30/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023]
Abstract
The performance of a semiconductor quantum-electronic device ultimately depends on the quality of the semiconductor materials it is made of and on how well the device is isolated from electrostatic fluctuations caused by unavoidable surface charges and other sources of electric noise. Current technology to fabricate quantum semiconductor devices relies on surface gates which impose strong limitations on the maximum distance from the surface where the confining electrostatic potentials can be engineered. Surface gates also introduce strain fields which cause imperfections in the semiconductor crystal structure. Another way to create confining electrostatic potentials inside semiconductors is by means of light and photosensitive dopants. Light can be structured in the form of perfectly parallel sheets of high and low intensity which can penetrate deep into a semiconductor and, importantly, light does not deteriorate the quality of the semiconductor crystal. In this work, we employ these important properties of structured light to form metastable states of photo-sensitive impurities inside a GaAs/AlGaAs quantum well structure in order to create persistent periodic electrostatic potentials at large predetermined distances from the sample surface. The amplitude of the light-induced potential is controlled by gradually increasing the light fluence at the sample surface and simultaneously measuring the amplitude of Weiss commensurability oscillations in the magnetoresistivity.
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Affiliation(s)
- Cyril Hnatovsky
- Emerging Technologies Division, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
| | - Stephen Mihailov
- Emerging Technologies Division, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
| | - Michael Hilke
- Department of Physics, McGill University, Montreal, QC H3A 2T8, Canada
| | - Loren Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Ken West
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Sergei Studenikin
- Emerging Technologies Division, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada
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Salimon IA, Zharkova EV, Averchenko AV, Kumar J, Somov P, Abbas OA, Lagoudakis PG, Mailis S. Laser-Synthesized 2D-MoS 2 Nanostructured Photoconductors. Micromachines (Basel) 2023; 14:mi14051036. [PMID: 37241659 DOI: 10.3390/mi14051036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023]
Abstract
The direct laser synthesis of periodically nanostructured 2D transition metal dichalcogenide (2D-TMD) films, from single source precursors, is presented here. Laser synthesis of MoS2 and WS2 tracks is achieved by localized thermal dissociation of Mo and W thiosalts, caused by the strong absorption of continuous wave (c.w.) visible laser radiation by the precursor film. Moreover, within a range of irradiation conditions we have observed occurrence of 1D and 2D spontaneous periodic modulation in the thickness of the laser-synthesized TMD films, which in some cases is so extreme that it results in the formation of isolated nanoribbons with a width of ~200 nm and a length of several micrometers. The formation of these nanostructures is attributed to the effect that is known as laser-induced periodic surface structures (LIPSS), which is caused by self-organized modulation of the incident laser intensity distribution due to optical feedback from surface roughness. We have fabricated two terminal photoconductive detectors based on nanostructured and continuous films and we show that the nanostructured TMD films exhibit enhanced photo-response, with photocurrent yield increased by three orders of magnitude as compared to their continuous counterparts.
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Affiliation(s)
- Igor A Salimon
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Ekaterina V Zharkova
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Aleksandr V Averchenko
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Jatin Kumar
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Pavel Somov
- Center for Energy Science and Technology (CEST), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Omar A Abbas
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Pavlos G Lagoudakis
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
| | - Sakellaris Mailis
- Center for Photonic Science and Engineering (CPhSE), Skolkovo Institute of Science and Technology, 3 Nobel Street, 143026 Moscow, Russia
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7
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Liu X, Li S, Li Z, Cao F, Su L, Shtansky DV, Fang X. Enhanced Response Speed in 2D Perovskite Oxides-Based Photodetectors for UV Imaging through Surface/Interface Carrier-Transport Modulation. ACS Appl Mater Interfaces 2022; 14:48936-48947. [PMID: 36273339 DOI: 10.1021/acsami.2c15946] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The long-time decay process induced by the persistent photoconductivity (PPC) in metal oxides-based photodetectors (PDs) impedes our demands for high-speed photodetectors. 2D perovskite oxides, emerging candidates for future high-performance PDs, also suffer from the PPC effect. Here, by integrating 2D perovskite Sr2Nb3O10 (SNO) nanosheets and nitrogen-doped graphene quantum dots (NGQDs), a unique nanoscale heterojunction is designed to modulate surface/interface carrier transport for enhanced response speed. Notably, the decay time is reduced from hundreds of seconds to a few seconds. The 4%NGQDs-SNO PD exhibits excellent performance with a photocurrent of 0.47 μA, a high on-off ratio of 2.2 × 104, and a fast pulse response speed (τdecay = 67.3 ms), making it promising for UV imaging. The trap-involved decay process plays a dominant role in determining the decay time, resulting in the PPC effect in SNO PD, and the trap states mainly originate from oxygen vacancies and chemisorbed oxygen molecules. A significantly enhanced photoresponse speed in NGQDs-SNO PDs can be ascribed to the modulated surface/interface trap states and the efficient carrier pathway provided by the nanoscale heterojunction. This work provides an effective way to enhance the response speed in 2D perovskite oxides constrained by PPC via surface/interface engineering, promoting their applications in optoelectronics.
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Affiliation(s)
- Xinya Liu
- Department of Materials Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai200433, P. R. China
| | - Siyuan Li
- Department of Chemistry, City University of Hong Kong, Hong Kong999077, P. R. China
| | - Ziqing Li
- Institute of Optoelectronics, Fudan University, Shanghai200433, P. R. China
| | - Fa Cao
- Department of Materials Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai200433, P. R. China
| | - Li Su
- Department of Materials Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai200433, P. R. China
| | - Dmitry V Shtansky
- National University of Science and Technology "MISIS", Leninsky Prospect 4, Moscow119049, Russia
| | - Xiaosheng Fang
- Department of Materials Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai200433, P. R. China
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Yoo S, Kim DS, Hong WK, Yoo JI, Huang F, Ko HC, Park JH, Yoon J. Enhanced Ultraviolet Photoresponse Characteristics of Indium Gallium Zinc Oxide Photo-Thin-Film Transistors Enabled by Surface Functionalization of Biomaterials for Real-Time Ultraviolet Monitoring. ACS Appl Mater Interfaces 2021; 13:47784-47792. [PMID: 34585581 DOI: 10.1021/acsami.1c15565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Indium gallium zinc oxide (IGZO) is one of the most promising materials for diverse optoelectronic applications based on thin-film transistors (TFTs) including ultraviolet (UV) photodetectors. In particular, the monitoring of UV-A (320-400 nm) exposure is very useful for healthcare applications because it can be used to prevent various human skin and eye-related diseases. However, the relatively weak optical absorption in the UV-A range and the persistent photoconductivity (PPC) arising from the oxygen vacancy-related states of IGZO thin films limit efficient UV monitoring. In this paper, we report the enhancement of the UV photoresponse characteristics of IGZO photo-TFTs by the surface functionalization of biomolecules on an IGZO channel. The biomaterial/IGZO interface plays a crucial role in enhancing UV-A absorption and suppressing PPC under negative gate bias, resulting in not only increased photoresponsivity and specific detectivity but also a fast and repeatable UV photoresponse. In addition, turning off the device without external bias completely eliminates PPC due to the internal electric field induced by the surface functionalization of biomaterials. Such a volatile feature of PPC enables the fast and repeatable UV photoresponse. These results suggest the potential of IGZO photo-TFTs combined with biomaterials for real-time UV monitoring.
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Affiliation(s)
- Seonggwang Yoo
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Da Som Kim
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Woong-Ki Hong
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Jung Il Yoo
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Fu Huang
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Heung Cho Ko
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Jung Hee Park
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
- Advanced Institute of Environment and Bioscience, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Jongwon Yoon
- Jeonju Center, Korea Basic Science Institute, Jeonju, Jeollabuk-do 54907, Republic of Korea
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9
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Ji YH, Gao Q, Huang AP, Yang MQ, Liu YQ, Geng XL, Zhang JJ, Wang RZ, Wang M, Xiao ZS, Chu PK. GaO x@GaN Nanowire Arrays on Flexible Graphite Paper with Tunable Persistent Photoconductivity. ACS Appl Mater Interfaces 2021; 13:41916-41925. [PMID: 34448583 DOI: 10.1021/acsami.1c13355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Flexible optoelectronic synaptic devices that functionally imitate the neural behavior with tunable optoelectronic characteristics are crucial to the development of advanced bioinspired neural networks. In this work, amorphous oxide-decorated GaN nanowire arrays (GaOx@GaN NWAs) are prepared on flexible graphite paper. A GaOx@GaN NWA-based flexible device has tunable persistent photoconductivity (PPC) and shows a conversible fast/slow decay process (SDP). Photoconductivity can be modulated by single or double light pulses with different illumination powers and biases. PPC gives rise to the high-performance SDP such as a long decay time of 2.3 × 105 s. The modulation mechanism is proposed and discussed. Our results reveal an innovative and efficient strategy to produce decorated NWAs on a flexible substrate with tunable optoelectronic properties and exhibit potential for flexible neuromorphic system applications.
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Affiliation(s)
- Yu-Hang Ji
- School of Physics, Beihang University, Beijing 100191, China
| | - Qin Gao
- School of Physics, Beihang University, Beijing 100191, China
| | - An-Ping Huang
- School of Physics, Beihang University, Beijing 100191, China
| | - Meng-Qi Yang
- Institute of New Energy Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Yan-Qi Liu
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 999077, China
| | - Xue-Li Geng
- School of Physics, Beihang University, Beijing 100191, China
| | - Jing-Jing Zhang
- School of Physics, Beihang University, Beijing 100191, China
| | - Ru-Zhi Wang
- Institute of New Energy Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Mei Wang
- School of Physics, Beihang University, Beijing 100191, China
| | - Zhi-Song Xiao
- School of Physics, Beihang University, Beijing 100191, China
| | - Paul K Chu
- Department of Physics, Department of Materials Science and Engineering, and Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 518057, Hong Kong, China
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10
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Butt MK, Zeeshan HM, Zhao Y, Wang S, Jin K. Controlling transport properties at LaFeO 3/SrTiO 3interfaces by defect engineering. J Phys Condens Matter 2021; 33:245001. [PMID: 33636709 DOI: 10.1088/1361-648x/abea40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
The formation of conductive LaFeO3/SrTiO3interfaces is first time reported by pulsed laser deposition via controlling the defects of SrTiO3, which are closely related to the surface of substrate. It is found that the interfaces grown on SrTiO3substrates without terraces exhibit the two dimensional electron gas. Moreover, the conductive interfaces show a resistance upturn at low temperatures which is strongly diminished by light irradiation. These interfaces favor the persistent photoconductivity, and the enormous value of relative change in resistance, about 60 185.8%, is also obtained at 20 K. The experimental results provide fundamental insights into controlling the defects at conductive interfaces of oxides and paving a way for complex-oxides based optoelectronic devices.
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Affiliation(s)
- Mehwish Khalid Butt
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Hafiz Muhammad Zeeshan
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Yang Zhao
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
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11
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Berweger S, Zhang H, Sahoo PK, Kupp BM, Blackburn JL, Miller EM, Wallis TM, Voronine DV, Kabos P, Nanayakkara SU. Spatially Resolved Persistent Photoconductivity in MoS 2-WS 2 Lateral Heterostructures. ACS Nano 2020; 14:14080-14090. [PMID: 33044054 DOI: 10.1021/acsnano.0c06745] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The optical and electronic properties of 2D semiconductors are intrinsically linked via the strong interactions between optically excited bound species and free carriers. Here we use near-field scanning microwave microscopy (SMM) to image spatial variations in photoconductivity in MoS2-WS2 lateral multijunction heterostructures using photon energy-resolved narrowband illumination. We find that the onset of photoconductivity in individual domains corresponds to the optical absorption onset, confirming that the tightly bound excitons in transition metal dichalcogenides can nonetheless dissociate into free carriers. These photogenerated carriers are most likely n-type and are seen to persist for up to days. Informed by finite element modeling we reveal that they can increase the carrier density by up to 200 times. This persistent photoconductivity appears to be dominated by contributions from the multilayer MoS2 domains, and we attribute the flake-wide response in part to charge transfer across the heterointerface. Spatial correlation of our SMM imaging with photoluminescence (PL) mapping confirms the strong link between PL peak emission photon energy, PL intensity, and the local accumulated charge. This work reveals the spatially and temporally complex optoelectronic response of these systems and cautions that properties measured during or after illumination may not reflect the true dark state of these materials but rather a metastable charged state.
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Affiliation(s)
- Samuel Berweger
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Hanyu Zhang
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Prasana K Sahoo
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
- Materials Science Centre, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Benjamin M Kupp
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
- The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jeffrey L Blackburn
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Elisa M Miller
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Thomas M Wallis
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Dmitri V Voronine
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Pavel Kabos
- Applied Physics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Sanjini U Nanayakkara
- Materials and Chemical Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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12
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Pei K, Wang F, Han W, Yang S, Liu K, Liu K, Li H, Zhai T. Suppression of Persistent Photoconductivity of Rubrene Crystals using Gate-Tunable Rubrene/Bi 2 Se 3 Diodes with Photoinduced Negative Differential Resistance. Small 2020; 16:e2002312. [PMID: 32627927 DOI: 10.1002/smll.202002312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/01/2020] [Indexed: 05/08/2023]
Abstract
Organic single-crystalline semiconductors show great potential in high-performance photodetectors. However, they suffer from persistent photoconductivity (PPC) due to the charge trapping, which has severely hindered high-speed imaging applications. Here, a universal strategy of solving the PPC by integrating with topological insulator Bi2 Se3 is provided. The rubrene/Bi2 Se3 heterojunctions are selected as an example for general demonstration due to the reproducibly high mobility and broad optoelectronic applications of rubrene crystals. By virtue of high carrier concentration on Bi2 Se3 surface and the strong built-in electrical field, the photoresponse of the heterotransistor is significantly reduced for more than two orders (from over 10 s to 54 ms), meanwhile the photoresponsivity can reach 124 A W-1 . To the best of knowledge, this operating speed is among the fastest responses in organic-inorganic heterojunctions. The heterotransistor also shows unique negative differential resistance under positive gate bias, which can be explained by photoinduced de-trapping of electron trap states in the bulk rubrene crystals. Besides, the rubrene/Bi2 Se3 heterojunction behaves as a gate-tunable backward-like diode due to the inhomogenous carrier distribution in the thick rubrene crystal and inversion of relative Fermi level positions. The findings demonstrate versatile functionalities of the rubrene/Bi2 Se3 heterojunctions for various emerging optoelectronic applications.
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Affiliation(s)
- Ke Pei
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Fakun Wang
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Wei Han
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Sanjun Yang
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Kailang Liu
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Kewei Liu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, P. R. China
| | - Huiqiao Li
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, P. R. China
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13
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Liu Z, Qiu H, Wang C, Chen Z, Zyska B, Narita A, Ciesielski A, Hecht S, Chi L, Müllen K, Samorì P. Photomodulation of Charge Transport in All-Semiconducting 2D-1D van der Waals Heterostructures with Suppressed Persistent Photoconductivity Effect. Adv Mater 2020; 32:e2001268. [PMID: 32378243 DOI: 10.1002/adma.202001268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/28/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Van der Waals heterostructures (VDWHs), obtained via the controlled assembly of 2D atomically thin crystals, exhibit unique physicochemical properties, rendering them prototypical building blocks to explore new physics and for applications in optoelectronics. As the emerging alternatives to graphene, monolayer transition metal dichalcogenides and bottom-up synthesized graphene nanoribbons (GNRs) are promising candidates for overcoming the shortcomings of graphene, such as the absence of a bandgap in its electronic structure, which is essential in optoelectronics. Herein, VDWHs comprising GNRs onto monolayer MoS2 are fabricated. Field-effect transistors (FETs) based on such VDWHs show an efficient suppression of the persistent photoconductivity typical of MoS2 , resulting from the interfacial charge transfer process. The MoS2 -GNR FETs exhibit drastically reduced hysteresis and more stable behavior in the transfer characteristics, which is a prerequisite for the further photomodulation of charge transport behavior within the MoS2 -GNR VDWHs. The physisorption of photochromic molecules onto the MoS2 -GNR VDWHs enables reversible light-driven control over charge transport. In particular, the drain current of the MoS2 -GNR FET can be photomodulated by 52%, without displaying significant fatigue over at least 10 cycles. Moreover, four distinguishable output current levels can be achieved, demonstrating the great potential of MoS2 -GNR VDWHs for multilevel memory devices.
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Affiliation(s)
- Zhaoyang Liu
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 Alleé Gaspard Monge, Strasbourg, F-67000, France
| | - Haixin Qiu
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 Alleé Gaspard Monge, Strasbourg, F-67000, France
| | - Can Wang
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 Alleé Gaspard Monge, Strasbourg, F-67000, France
| | - Zongping Chen
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Björn Zyska
- Department of Chemistry and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, 12489, Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami, Okinawa, 904-0495, Japan
| | - Artur Ciesielski
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 Alleé Gaspard Monge, Strasbourg, F-67000, France
| | - Stefan Hecht
- Department of Chemistry and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, 12489, Germany
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, Aachen, 52056, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringer Weg 2, Aachen, 52074, Germany
| | - Lifeng Chi
- Jiangsu Key Laboratory for Carbon Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, P. R. China
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Paolo Samorì
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 Alleé Gaspard Monge, Strasbourg, F-67000, France
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14
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Kim MK, Lee JS. Synergistic Improvement of Long-Term Plasticity in Photonic Synapses Using Ferroelectric Polarization in Hafnia-Based Oxide-Semiconductor Transistors. Adv Mater 2020; 32:e1907826. [PMID: 32053265 DOI: 10.1002/adma.201907826] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/04/2020] [Indexed: 06/10/2023]
Abstract
A number of synapse devices have been intensively studied for the neuromorphic system which is the next-generation energy-efficient computing method. Among these various types of synapse devices, photonic synapse devices recently attracted significant attention. In particular, the photonic synapse devices using persistent photoconductivity (PPC) phenomena in oxide semiconductors are receiving much attention due to the similarity between relaxation characteristics of PPC phenomena and Ca2+ dynamics of biological synapses. However, these devices have limitations in its controllability of the relaxation characteristics of PPC behaviors. To utilize the oxide semiconductor as photonic synapse devices, relaxation behavior needs to be accurately controlled. In this study, a photonic synapse device with controlled relaxation characteristics by using an oxide semiconductor and a ferroelectric layer is demonstrated. This device exploits the PPC characteristics to demonstrate synaptic functions including short-term plasticity, paired-pulse facilitation (PPF), and long-term plasticity (LTP). The relaxation properties are controlled by the polarization of the ferroelectric layer, and this polarization is used to control the amount by which the conductance levels increase during PPF operation and to enhance LTP characteristics. This study provides an important step toward the development of photonic synapses with tunable synaptic functions.
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Affiliation(s)
- Min-Kyu Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Jang-Sik Lee
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
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15
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Snyder PJ, LaJeunesse DR, Reddy P, Kirste R, Collazo R, Ivanisevic A. Bioelectronics communication: encoding yeast regulatory responses using nanostructured gallium nitride thin films. Nanoscale 2018; 10:11506-11516. [PMID: 29888776 PMCID: PMC6195121 DOI: 10.1039/c8nr03684e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Baker's yeast, S. cerevisiae, is a model organism that is used in synthetic biology. The work demonstrates how GaN nanostructured thin films can encode physiological responses in S. cerevisiae yeast. The Ga-polar, n-type, GaN thin films are characterized via Photocurrent Measurements, Atomic Force Microscopy and Kelvin Probe Force Microscopy. UV light is used to induce persistent photoconductivity that results in charge accumulation on the surface. The morphological, chemical and electronic properties of the nanostructured films are utilized to activate the cell wall integrity pathway and alter the amount of chitin produced by the yeast. The encoded cell responses are induced by the semiconductor interfacial properties associated with nanoscale topography and the accumulation of charge on the surface that promotes the build-up of oxygen species and in turn cause a hyperoxia related change in the yeast. The thin films can also alter the membrane voltage of yeast. The observed modulation of the membrane voltage of the yeast exposed to different GaN samples supports the notion that the semiconductor material can cause cell polarization. The results thus define a strategy for bioelectronics communication where the roughness, surface chemistry and charge of the wide band gap semiconductor's thin film surface initiate the encoding of the yeast response.
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Affiliation(s)
- Patrick J Snyder
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
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16
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Wang L, Chen P, Wang YC, Liu GS, Liu C, Xie X, Li JZ, Yang BR. Tape-Based Photodetector: Transfer Process and Persistent Photoconductivity. ACS Appl Mater Interfaces 2018; 10:16596-16604. [PMID: 29687705 DOI: 10.1021/acsami.8b02233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report a facile transfer method to fabricate flexible photodetectors directly on tape, wherein the films formed by different processes were integrated together. The tape-based photodetectors with CdS nanowire (NW) active layers exhibited good performances as those fabricated by conventional processes. The obvious persistent photocurrent in our device was eliminated by introducing a conductive polymer poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS) onto the CdS NW layer. By adjusting the concentration of the PEDOT:PSS aqueous solution, a device with a fast response, ultrashort decay time, and relatively large photocurrent was obtained. The decay times were 11.59 and 6.64 ms for devices using electrodes of silver NWs and gold, respectively. These values are much shorter than the shortest decay times (on the order of hundreds of milliseconds) reported previously.
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Affiliation(s)
- Li Wang
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Peng Chen
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Yu-Cheng Wang
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Gui-Shi Liu
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Chuan Liu
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Xi Xie
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Jing-Zhou Li
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
| | - Bo-Ru Yang
- School of Electronics and Information Technology, State Key Laboratory of Opto-Electronic Materials & Technologies, Guangdong Province Key Laboratory of Display Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , People's Republic of China
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17
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Yan H, Zhang Z, Wang S, Wei X, Chen C, Jin K. Magnetism Control by Doping in LaAlO 3/SrTiO 3 Heterointerfaces. ACS Appl Mater Interfaces 2018; 10:14209-14213. [PMID: 29619833 DOI: 10.1021/acsami.8b03275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Magnetic two-dimensional electron gases at the oxide interfaces are always one of the key issues in spintronics, giving rise to intriguing magnetotransport properties. However, reports about magnetic two-dimensional electron gases remain elusive. Here, we obtain the magnetic order of LaAlO3/SrTiO3 systems by introducing magnetic dopants at the La site. The transport properties with a characteristic of metallic behavior at the interfaces are investigated. More significantly, magnetic-doped samples exhibit obvious magnetic hysteresis loops and the mobility is enhanced. Meanwhile, the photoresponsive experiments are realized by irradiating all samples with a 360 nm light. Compared to magnetism, the effects of dopants on photoresponsive and relaxation properties are negligible because the behavior originates from SrTiO3 substrates. This work paves a way for revealing and better controlling the magnetic properties of oxide heterointerfaces.
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Affiliation(s)
- Hong Yan
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
| | - Zhaoting Zhang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
| | - Xiangyang Wei
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
| | - Changle Chen
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science , Northwestern Polytechnical University , Xi'an 710072 , China
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18
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Tran MD, Kim JH, Kim H, Doan MH, Duong DL, Lee YH. Role of Hole Trap Sites in MoS 2 for Inconsistency in Optical and Electrical Phenomena. ACS Appl Mater Interfaces 2018; 10:10580-10586. [PMID: 29504404 DOI: 10.1021/acsami.8b00541] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Because of strong Coulomb interaction in two-dimensional van der Waals-layered materials, the trap charges at the interface strongly influence the scattering of the majority carriers and thus often degrade their electrical properties. However, the photogenerated minority carriers can be trapped at the interface, modulate the electron-hole recombination, and eventually influence the optical properties. In this study, we report the role of the hole trap sites on the inconsistency in the electrical and optical phenomena between two systems with different interfacial trap densities, which are monolayer MoS2-based field-effect transistors (FETs) on hexagonal boron nitride (h-BN) and SiO2 substrates. Electronic transport measurements indicate that the use of h-BN as a gate insulator can induce a higher n-doping concentration of the monolayer MoS2 by suppressing the free-electron transfer from the intrinsically n-doped MoS2 to the SiO2 gate insulator. Nevertheless, optical measurements show that the electron concentration in MoS2/SiO2 is heavier than that in MoS2/h-BN, manifested by the relative red shift of the A1g Raman peak. The inconsistency in the evaluation of the electron concentration in MoS2 by electrical and optical measurements is explained by the trapping of the photogenerated holes in the spatially modulated valence band edge of the monolayer MoS2 caused by the local strain from the SiO2/Si substrate. This photoinduced electron doping in MoS2/SiO2 is further confirmed by the development of the trion component in the power-dependent photoluminescence spectra and negative shift of the threshold voltage of the FET after illumination.
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Affiliation(s)
- Minh Dao Tran
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
| | - Ji-Hee Kim
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
| | - Hyun Kim
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
| | - Manh Ha Doan
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
| | - Dinh Loc Duong
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics , Institute for Basic Science (IBS) , Suwon 16419 , Republic of Korea
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19
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Hu DC, Yang R, Jiang L, Guo X. Memristive Synapses with Photoelectric Plasticity Realized in ZnO 1-x/AlO y Heterojunction. ACS Appl Mater Interfaces 2018; 10:6463-6470. [PMID: 29388420 DOI: 10.1021/acsami.8b01036] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
With the end of Moore's law in sight, new computing architectures are urgently needed to satisfy the increasing demands for big data processing. Neuromorphic architectures with photoelectric learning capability are good candidates for energy-efficient computing for recognition and classification tasks. In this work, artificial synapses based on the ZnO1-x/AlOy heterojunction were fabricated and the photoelectric plasticity was investigated. Versatile synaptic functions such as photoelectric short-term/long-term plasticity, paired-pulse facilitation, neuromorphic facilitation, and depression were emulated based on the inherent persistent photoconductivity and volatile resistive switching characteristics of the device. It is found that the naturally formed AlOy layer provides traps for photogenerated holes, resulting in a significant persistent photoconductivity effect. Moreover, the resistive switching can be attributed to the electron trapping/detrapping at the trapping sites in the AlOy layer.
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Affiliation(s)
- Dan-Chun Hu
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Rui Yang
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Li Jiang
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Xin Guo
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
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20
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Yan H, Zhang Z, Wang S, Zhang H, Chen C, Jin K. Modulated Transport Behavior of Two-Dimensional Electron Gas at Ni-Doped LaAlO 3/SrTiO 3 Heterointerfaces. ACS Appl Mater Interfaces 2017; 9:39011-39017. [PMID: 29034682 DOI: 10.1021/acsami.7b11727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Modulating transport behaviors of two-dimensional electron gases are of critical importance for applications of the next-generation multifunctional oxide electronics. In this study, transport behaviors of LaAlO3/SrTiO3 heterointerfaces modified through the Ni dopant and the light irradiation have been investigated. Through the Ni dopant, the resistances increase significantly and a resistance upturn phenomenon due to the Kondo effect is observed at T < 40 K. Under a 360 nm light irradiation, the interfaces exhibit a persistent photoconductivity and a suppressed Kondo effect at low temperature due to the increased mobility measured through the photo-Hall method. Moreover, the relative changes in resistance of interfaces induced by light are increased from 800 to 6600% at T = 12 K with increasing the substitution of Ni, which is discussed by the band bending and the lattice effect due to the Ni dopant. This work paves the way for better controlling the emerging properties of complex oxide heterointerfaces and would be helpful for photoelectric device applications based on all-oxides.
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Affiliation(s)
- Hong Yan
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
| | - Zhaoting Zhang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
| | - Hongrui Zhang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
| | - Changle Chen
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University , Xi'an 710072, China
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21
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Ibrahem MA, Verrelli E, Lai KT, Kyriakou G, Lee AF, Isaacs MA, Cheng F, O'Neill M. Dual Wavelength (Ultraviolet and Green) Photodetectors Using Solution Processed Zinc Oxide Nanoparticles. ACS Appl Mater Interfaces 2017; 9:36971-36979. [PMID: 28950063 DOI: 10.1021/acsami.7b08092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Narrow-band photoconductivity with a spectral width of 0.16 eV is obtained from solution-processed colloidal ZnO nanocrystals beneath the band-edge at 2.25 eV. A new model involving electron transfer from deep defects to discrete shallow donors is introduced to explain the narrow spectrum and the exponential form of the current rise and decay transients. The defects are tentatively assigned to neutral oxygen vacancies. The photocurrent responsivity can be enhanced by storage in air, and this correlates with the formation of carbonate surface species by capture of carbon dioxide during storage. This controllability is exploited to develop a low-cost and scalable photolithographic approach to pixelate photodetectors for applications such as object discrimination, sensing, etc. The spectral response can be spatially patterned so that dual (ultraviolet and green) and single (ultraviolet only) wavelength detecting ZnO pixels can be produced on the same substrate. This presents a new sensor mode with applications in security or full color imaging.
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Affiliation(s)
- Mohammed A Ibrahem
- School of Mathematics and Physical Sciences, University of Hull , Cottingham Road, Kingston upon Hull HU6 7RX, United Kingdom
- Laser Physics Branch, Department of Applied Sciences, University of Technology , Baghdad 10066, Iraq
| | - Emanuele Verrelli
- School of Mathematics and Physical Sciences, University of Hull , Cottingham Road, Kingston upon Hull HU6 7RX, United Kingdom
| | - Khue T Lai
- School of Engineering and Computer Science, University of Hull , Cottingham Road, Kingston upon Hull HU6 7RX, United Kingdom
| | - Georgios Kyriakou
- European Bioenergy Research Institute, Aston University , Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Adam F Lee
- European Bioenergy Research Institute, Aston University , Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Mark A Isaacs
- European Bioenergy Research Institute, Aston University , Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Fei Cheng
- School of Mathematics and Physical Sciences, University of Hull , Cottingham Road, Kingston upon Hull HU6 7RX, United Kingdom
| | - Mary O'Neill
- School of Mathematics and Physical Sciences, University of Hull , Cottingham Road, Kingston upon Hull HU6 7RX, United Kingdom
- School of Science and Technology, Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS, United Kingdom
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22
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Lee M, Lee W, Choi S, Jo JW, Kim J, Park SK, Kim YH. Brain-Inspired Photonic Neuromorphic Devices using Photodynamic Amorphous Oxide Semiconductors and their Persistent Photoconductivity. Adv Mater 2017; 29:1700951. [PMID: 28514064 DOI: 10.1002/adma.201700951] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 03/19/2017] [Indexed: 05/22/2023]
Abstract
The combination of a neuromorphic architecture and photonic computing may open up a new era for computational systems owing to the possibility of attaining high bandwidths and the low-computation-power requirements. Here, the demonstration of photonic neuromorphic devices based on amorphous oxide semiconductors (AOSs) that mimic major synaptic functions, such as short-term memory/long-term memory, spike-timing-dependent plasticity, and neural facilitation, is reported. The synaptic functions are successfully emulated using the inherent persistent photoconductivity (PPC) characteristic of AOSs. Systematic analysis of the dynamics of photogenerated carriers for various AOSs is carried out to understand the fundamental mechanisms underlying the photoinduced carrier-generation and relaxation behaviors, and to search for a proper channel material for photonic neuromorphic devices. It is found that the activation energy for the neutralization of ionized oxygen vacancies has a significant influence on the photocarrier-generation and time-variant recovery behaviors of AOSs, affecting the PPC behavior.
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Affiliation(s)
- Minkyung Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
| | - Woobin Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
| | - Seungbeom Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
| | - Jeong-Wan Jo
- School of Electrical and Electronic Engineering, Chung-Ang University, Seoul, 06980, Korea
| | - Jaekyun Kim
- Department of Photonics and Nanoelectronics, Hanyang University, Ansan, 15588, Korea
| | - Sung Kyu Park
- School of Electrical and Electronic Engineering, Chung-Ang University, Seoul, 06980, Korea
| | - Yong-Hoon Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, Korea
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Snyder PJ, Kirste R, Collazo R, Ivanisevic A. Persistent Photoconductivity, Nanoscale Topography, and Chemical Functionalization Can Collectively Influence the Behavior of PC12 Cells on Wide Bandgap Semiconductor Surfaces. Small 2017; 13:1700481. [PMID: 28464526 DOI: 10.1002/smll.201700481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 03/15/2017] [Indexed: 06/07/2023]
Abstract
Wide bandgap semiconductors such as gallium nitride (GaN) exhibit persistent photoconductivity properties. The incorporation of this asset into the fabrication of a unique biointerface is presented. Templates with lithographically defined regions with controlled roughness are generated during the semiconductor growth process. Template surface functional groups are varied using a benchtop surface functionalization procedure. The conductivity of the template is altered by exposure to UV light and the behavior of PC12 cells is mapped under different substrate conductivity. The pattern size and roughness are combined with surface chemistry to change the adhesion of PC12 cells when the GaN is made more conductive after UV light exposure. Furthermore, during neurite outgrowth, surface chemistry and initial conductivity difference are used to facilitate the extension to smoother areas on the GaN surface. These results can be utilized for unique bioelectronics interfaces to probe and control cellular behavior.
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Affiliation(s)
- Patrick J Snyder
- Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27606, USA
| | - Ronny Kirste
- Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27606, USA
- Adroit Materials, 2054 Kildaire Farm Rd., Suite 205, Cary, NC, 27518, USA
| | - Ramon Collazo
- Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27606, USA
| | - Albena Ivanisevic
- Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27606, USA
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24
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Jang JT, Park J, Ahn BD, Kim DM, Choi SJ, Kim HS, Kim DH. Study on the photoresponse of amorphous In-Ga-Zn-O and zinc oxynitride semiconductor devices by the extraction of sub-gap-state distribution and device simulation. ACS Appl Mater Interfaces 2015; 7:15570-15577. [PMID: 26094854 DOI: 10.1021/acsami.5b04152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Persistent photoconduction (PPC) is a phenomenon that limits the application of oxide semiconductor thin-film transistors (TFTs) in optical sensor-embedded displays. In the present work, a study on zinc oxynitride (ZnON) semiconductor TFTs based on the combination of experimental results and device simulation is presented. Devices incorporating ZnON semiconductors exhibit negligible PPC effects compared with amorphous In-Ga-Zn-O (a-IGZO) TFTs, and the difference between the two types of materials are examined by monochromatic photonic C-V spectroscopy (MPCVS). The latter method allows the estimation of the density of subgap states in the semiconductor, which may account for the different behavior of ZnON and IGZO materials with respect to illumination and the associated PPC. In the case of a-IGZO TFTs, the oxygen flow rate during the sputter deposition of a-IGZO is found to influence the amount of PPC. Small oxygen flow rates result in pronounced PPC, and large densities of valence band tail (VBT) states are observed in the corresponding devices. This implies a dependence of PPC on the amount of oxygen vacancies (VO). On the other hand, ZnON has a smaller bandgap than a-IGZO and contains a smaller density of VBT states over the entire range of its bandgap energy. Here, the concept of activation energy window (AEW) is introduced to explain the occurrence of PPC effects by photoinduced electron doping, which is likely to be associated with the formation of peroxides in the semiconductor. The analytical methodology presented in this report accounts well for the reduction of PPC in ZnON TFTs, and provides a quantitative tool for the systematic development of phototransistors for optical sensor-embedded interactive displays.
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Affiliation(s)
- Jun Tae Jang
- †School of Electrical Engineering, Kookmin University, Seoul 136-702, Republic of Korea
| | - Jozeph Park
- ‡Department of Materials Science and Engineering, KAIST, Daejeon 305-338, Republic of Korea
| | - Byung Du Ahn
- §School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, Republic of Korea
| | - Dong Myong Kim
- †School of Electrical Engineering, Kookmin University, Seoul 136-702, Republic of Korea
| | - Sung-Jin Choi
- †School of Electrical Engineering, Kookmin University, Seoul 136-702, Republic of Korea
| | - Hyun-Suk Kim
- #Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Dae Hwan Kim
- †School of Electrical Engineering, Kookmin University, Seoul 136-702, Republic of Korea
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25
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Huang L, Lin CC, Riediger M, Röder R, Tse PL, Ronning C, Lu JG. Nature of AX centers in antimony-doped cadmium telluride nanobelts. Nano Lett 2015; 15:974-980. [PMID: 25602598 DOI: 10.1021/nl503781u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Single crystalline p-type CdTe:Sb nanobelts were fabricated using an Au-catalyzed chemical vapor deposition method. Low carrier concentration and low mobility even at high Sb incorporation manifest compensation in the system. From cross examination of temperature-dependent charge transport and photoluminescence measurements, two major acceptor levels induced by Sb doping are determined: a shallow level attributed to substitutional Sb dopants without lattice relaxation and an associated deeper level resulted from large lattice relaxation-AX centers. Persistent photoconductivity and hysteresis photoconductance under the thermal cycle elucidate the nature of AX centers. This comprehensive investigation of the impurity levels in the material system is essential for the design and development of nanoelectronic devices based on the CdTe nanostructures.
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Affiliation(s)
- Liubing Huang
- Department of Physics and Department of Electrical Engineering, University of Southern California , Los Angeles, California 90089-0484, United States
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26
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Abstract
A drastic change in the conductivity of strained BiFeO3 (BFO) films is observed after illuminating them with above-band gap light. This has been termed as persistent photoconductivity. The enhanced conductivity decays exponentially with time. A trapping character of the sub-band levels and their subsequent gradual emptying is proposed as a possible mechanism.
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Affiliation(s)
- Akash Bhatnagar
- Max Planck Institute of Microstructure Physics , Weinberg 2, 06120 Halle, Germany
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27
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Moore JC, Thompson CV. A phenomenological model for the photocurrent transient relaxation observed in ZnO-based photodetector devices. Sensors (Basel) 2013; 13:9921-40. [PMID: 23921826 PMCID: PMC3812587 DOI: 10.3390/s130809921] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 11/16/2022]
Abstract
We present a phenomenological model for the photocurrent transient relaxation observed in ZnO-based metal-semiconductor-metal (MSM) planar photodetector devices based on time-resolved surface band bending. Surface band bending decreases during illumination, due to migration of photogenerated holes to the surface. Immediately after turning off illumination, conduction-band electrons must overcome a relatively low energy barrier to recombine with photogenerated holes at the surface; however, with increasing time, the adsorption of oxygen at the surface or electron trapping in the depletion region increases band bending, resulting in an increased bulk/surface energy barrier that slows the transport of photogenerated electrons. We present a complex rate equation based on thermionic transition of charge carriers to and from the surface and numerically fit this model to transient photocurrent measurements of several MSM planar ZnO photodetectors at variable temperature. Fitting parameters are found to be consistent with measured values in the literature. An understanding of the mechanism for persistent photoconductivity could lead to mitigation in future device applications.
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Affiliation(s)
- James C Moore
- Department of Chemistry and Physics, Coastal Carolina University, Conway, SC 29528, USA.
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