1
|
Matson J, Wasserroth S, Ni X, Obst M, Diaz-Granados K, Carini G, Renzi EM, Galiffi E, Folland TG, Eng LM, Michael Klopf J, Mastel S, Armster S, Gambin V, Wolf M, Kehr SC, Alù A, Paarmann A, Caldwell JD. Controlling the propagation asymmetry of hyperbolic shear polaritons in beta-gallium oxide. Nat Commun 2023; 14:5240. [PMID: 37640711 PMCID: PMC10462611 DOI: 10.1038/s41467-023-40789-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/07/2023] [Indexed: 08/31/2023] Open
Abstract
Structural anisotropy in crystals is crucial for controlling light propagation, particularly in the infrared spectral regime where optical frequencies overlap with crystalline lattice resonances, enabling light-matter coupled quasiparticles called phonon polaritons (PhPs). Exploring PhPs in anisotropic materials like hBN and MoO3 has led to advancements in light confinement and manipulation. In a recent study, PhPs in the monoclinic crystal β-Ga2O3 (bGO) were shown to exhibit strongly asymmetric propagation with a frequency dispersive optical axis. Here, using scanning near-field optical microscopy (s-SNOM), we directly image the symmetry-broken propagation of hyperbolic shear polaritons in bGO. Further, we demonstrate the control and enhancement of shear-induced propagation asymmetry by varying the incident laser orientation and polariton momentum using different sizes of nano-antennas. Finally, we observe significant rotation of the hyperbola axis by changing the frequency of incident light. Our findings lay the groundwork for the widespread utilization and implementation of polaritons in low-symmetry crystals.
Collapse
Affiliation(s)
| | - Sören Wasserroth
- Fritz Haber Institute of the Max Planck Society, Berlin, Germany
| | - Xiang Ni
- School of Physics, Central South University, Changsha, Hunan, China
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA
| | - Maximilian Obst
- Institute of Applied Physics, TUD Dresden University of Technology, Dresden, Germany
| | | | - Giulia Carini
- Fritz Haber Institute of the Max Planck Society, Berlin, Germany
| | - Enrico Maria Renzi
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA
- Physics Program, Graduate Center, City University of New York, New York, NY, USA
| | - Emanuele Galiffi
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA
| | | | - Lukas M Eng
- Institute of Applied Physics, TUD Dresden University of Technology, Dresden, Germany
| | | | | | - Sean Armster
- NG NEXT, Northrop Grumman Corporation, Redondo Beach, CA, USA
| | - Vincent Gambin
- NG NEXT, Northrop Grumman Corporation, Redondo Beach, CA, USA
| | - Martin Wolf
- Fritz Haber Institute of the Max Planck Society, Berlin, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, TUD Dresden University of Technology, Dresden, Germany
| | - Andrea Alù
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA
- Physics Program, Graduate Center, City University of New York, New York, NY, USA
| | | | | |
Collapse
|
2
|
Zhang X, Jin Z, Wang L, Hachtel JA, Villarreal E, Wang Z, Ha T, Nakanishi Y, Tiwary CS, Lai J, Dong L, Yang J, Vajtai R, Ringe E, Idrobo JC, Yakobson BI, Lou J, Gambin V, Koltun R, Ajayan PM. Low Contact Barrier in 2H/1T' MoTe 2 In-Plane Heterostructure Synthesized by Chemical Vapor Deposition. ACS Appl Mater Interfaces 2019; 11:12777-12785. [PMID: 30854848 DOI: 10.1021/acsami.9b00306] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Metal-semiconductor contact has been a critical topic in the semiconductor industry because it influences device performance remarkably. Conventional metals have served as the major contact material in electronic and optoelectronic devices, but such a selection becomes increasingly inadequate for emerging novel materials such as two-dimensional (2D) materials. Deposited metals on semiconducting 2D channels usually form large resistance contacts due to the high Schottky barrier. A few approaches have been reported to reduce the contact resistance but they are not suitable for large-scale application or they cannot create a clean and sharp interface. In this study, a chemical vapor deposition (CVD) technique is introduced to produce large-area semiconducting 2D material (2H MoTe2) planarly contacted by its metallic phase (1T' MoTe2). We demonstrate the phase-controllable synthesis and systematic characterization of large-area MoTe2 films, including pure 2H phase or 1T' phase, and 2H/1T' in-plane heterostructure. Theoretical simulation shows a lower Schottky barrier in 2H/1T' junction than in Ti/2H contact, which is confirmed by electrical measurement. This one-step CVD method to synthesize large-area, seamless-bonding 2D lateral metal-semiconductor junction can improve the performance of 2D electronic and optoelectronic devices, paving the way for large-scale 2D integrated circuits.
Collapse
Affiliation(s)
| | | | | | - Jordan A Hachtel
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | | | | | - Teresa Ha
- NG Next, Northrop Grumman Corporation , Redondo Beach , California 90278 , United States
| | | | - Chandra Sekhar Tiwary
- Metallurgical and Materials Engineering , Indian Institute of Technology Kharagpur , West Bengal 721301 , India
| | | | | | | | - Robert Vajtai
- Interdisciplinary Excellence Centre, Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér1. , Szeged , Hungary
| | | | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | | | | | - Vincent Gambin
- NG Next, Northrop Grumman Corporation , Redondo Beach , California 90278 , United States
| | - Rachel Koltun
- NG Next, Northrop Grumman Corporation , Redondo Beach , California 90278 , United States
| | | |
Collapse
|
3
|
Liu Y, Guo J, Zhu E, Wang P, Gambin V, Huang Y, Duan X. Maximizing the Current Output in Self-Aligned Graphene-InAs-Metal Vertical Transistors. ACS Nano 2019; 13:847-854. [PMID: 30615830 DOI: 10.1021/acsnano.8b08617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
With finite density of states and electrostatically tunable work function, graphene can function as a tunable contact for a semiconductor channel to enable vertical field-effect transistors (VFETs). However, the overall performance, especially the output current density, is still limited by the low conductance of the vertical semiconductor channel, as well as large series resistance of the graphene electrode. To overcome these limitations, we construct a VFET by using single-crystal InAs film as the high-conductance vertical channel and self-aligned metal contact as the source-drain electrodes, resulting in a record high current density over 45 000 A/cm2 at a low bias voltage of 1 V. Furthermore, we construct a device-level VFET model using the resistor network method, and experimentally validate the impact of each geometry parameter on device performance. Importantly, we found the device performance is not only a function of the intrinsic channel material, but also greatly influenced by device geometries and footprint. Our study not only pushes the performance limit of graphene VFETs, but also sheds light on van der Waals integration between two-dimensional material and conventional bulk material for high-performance VFETs and circuits.
Collapse
Affiliation(s)
- Yuan Liu
- Department of Materials Science and Engineering , University of California , Los Angeles , California 90095 , United States
- Hunan Key Laboratory of Two-Dimensional Materials and State Key Laboratory for Chemo/Biosensing and Chemometrics, School of Physics and Electronics , Hunan University , Changsha 410082 , China
| | - Jian Guo
- Department of Materials Science and Engineering , University of California , Los Angeles , California 90095 , United States
| | - Enbo Zhu
- Department of Materials Science and Engineering , University of California , Los Angeles , California 90095 , United States
| | - Peiqi Wang
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Vincent Gambin
- NG NEXT , Northrop Grumman Aerospace Systems , Redondo Beach , California 90278 , United States
| | - Yu Huang
- Department of Materials Science and Engineering , University of California , Los Angeles , California 90095 , United States
- California Nanosystems Institute , University of California , Los Angeles , California 90095 , United States
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
- California Nanosystems Institute , University of California , Los Angeles , California 90095 , United States
| |
Collapse
|
4
|
Barako MT, Gambin V, Tice J. Integrated nanomaterials for extreme thermal management: a perspective for aerospace applications. Nanotechnology 2018; 29:154003. [PMID: 29384132 DOI: 10.1088/1361-6528/aaabe1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanomaterials will play a disruptive role in next-generation thermal management for high power electronics in aerospace platforms. These high power and high frequency devices have been experiencing a paradigm shift toward designs that favor extreme integration and compaction. The reduction in form factor amplifies the intensity of the thermal loads and imposes extreme requirements on the thermal management architecture for reliable operation. In this perspective, we introduce the opportunities and challenges enabled by rationally integrating nanomaterials along the entire thermal resistance chain, beginning at the high heat flux source up to the system-level heat rejection. Using gallium nitride radio frequency devices as a case study, we employ a combination of viewpoints comprised of original research, academic literature, and industry adoption of emerging nanotechnologies being used to construct advanced thermal management architectures. We consider the benefits and challenges for nanomaterials along the entire thermal pathway from synthetic diamond and on-chip microfluidics at the heat source to vertically-aligned copper nanowires and nanoporous media along the heat rejection pathway. We then propose a vision for a materials-by-design approach to the rational engineering of complex nanostructures to achieve tunable property combinations on demand. These strategies offer a snapshot of the opportunities enabled by the rational design of nanomaterials to mitigate thermal constraints and approach the limits of performance in complex aerospace electronics.
Collapse
Affiliation(s)
- Michael T Barako
- NG Next, Northrop Grumman Corporation, Redondo Beach, CA 90278, United States of America
| | | | | |
Collapse
|
5
|
Liu Y, Guo J, He Q, Wu H, Cheng HC, Ding M, Shakir I, Gambin V, Huang Y, Duan X. Vertical Charge Transport and Negative Transconductance in Multilayer Molybdenum Disulfides. Nano Lett 2017; 17:5495-5501. [PMID: 28823157 DOI: 10.1021/acs.nanolett.7b02161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Negative transconductance (NTC) devices have been heavily investigated for their potential in low power logical circuit, memory, oscillating, and high-speed switching applications. Previous NTC devices are largely attributed to two working mechanisms: quantum mechanical tunneling, and mobility degradation at high electrical field. Herein we report a systematic investigation of charge transport in multilayer two-dimensional semiconductors (2DSCs) with optimized van der Waals contact and for the first time demonstrate NTC and antibipolar characteristics in multilayer 2DSCs (such as MoS2, WSe2). By varying the measurement temperature, bias voltage, and body thickness, we found the NTC behavior can be attributed to a vertical potential barrier in the multilayer 2DSCs and the competing mechanisms between intralayer lateral transport and interlayer vertical transport, thus representing a new working mechanism for NTC operation. Importantly, this vertical potential barrier arises from inhomogeneous carrier distribution in 2DSC from the near-substrate region to the bulk region, which is in contrast to conventional semiconductors with homogeneous doping defined by bulk dopants. We further show that the unique NTC behavior can be explored for creating frequency doublers and phase shift keying circuits with only one transistor, greatly simplifying the circuit design compared to conventional technology.
Collapse
Affiliation(s)
- Yuan Liu
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Jian Guo
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Qiyuan He
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Hao Wu
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Hung-Chieh Cheng
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Mengning Ding
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Imran Shakir
- Sustainable Energy Technologies Centre, College of Engineering, King Saud University , Riyadh 11421, Kingdom of Saudi Arabia
| | - Vincent Gambin
- NG/NEXT, Northrop Grumman Corporation, Redondo Beach, California 90278, United States
| | - Yu Huang
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
- California Nanosystems Institute, University of California , Los Angeles, California 90095, United States
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
- California Nanosystems Institute, University of California , Los Angeles, California 90095, United States
| |
Collapse
|
6
|
Abstract
Vertical heterostructures based on graphene have emerged as a unique architecture for novel electronic devices with unusual characteristics. Here we report a new design of vertical ambipolar barristors based on metal-graphene-silicon-graphene sandwich structure, using the bottom graphene as a gate-tunable "active contact", the top graphene as an adaptable Ohmic contact, and the low doping thin silicon layer as the switchable channel. Importantly, with finite density of states and weak screening effect of graphene, we demonstrate, for the first time, that both the carrier concentration and majority carrier type in the sandwiched silicon can be readily modulated by gate potential penetrating through graphene. It can thus enable a new type of ambipolar barristors with an ON-OFF ratio exceeding 103. Significantly, these ambipolar barristors can be flexibly configured into either p-type or n-type transistors and used to create integrated circuits with reconfigurable logic functions. This unconventional device structure and ambipolar reconfigurable characteristics can open up exciting opportunities in future electronics based on graphene or two-dimensional van der Waals heterostructures.
Collapse
Affiliation(s)
- Yuan Liu
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Guo Zhang
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Hailong Zhou
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Zheng Li
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Rui Cheng
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
| | - Yang Xu
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Vincent Gambin
- NG/NEXT, Northrop Grumman Aerospace Systems, Redondo Beach, California 90278, United States
| | - Yu Huang
- Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States
- California Nanosystems Institute, University of California , Los Angeles, California 90095, United States
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
- California Nanosystems Institute, University of California , Los Angeles, California 90095, United States
| |
Collapse
|
7
|
Kwon SY, Ciobanu CV, Petrova V, Shenoy VB, Bareño J, Gambin V, Petrov I, Kodambaka S. Growth of semiconducting graphene on palladium. Nano Lett 2009; 9:3985-3990. [PMID: 19995079 DOI: 10.1021/nl902140j] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report in situ scanning tunneling microscopy studies of graphene growth on Pd(111) during ethylene deposition at temperatures between 723 and 1023 K. We observe the formation of monolayer graphene islands, 200-2000 A in size, bounded by Pd surface steps. Surprisingly, the topographic image contrast from graphene islands reverses with tunneling bias, suggesting a semiconducting behavior. Scanning tunneling spectroscopy measurements confirm that the graphene islands are semiconducting, with a band gap of 0.3 +/- 0.1 eV. On the basis of density functional theory calculations, we suggest that the opening of a band gap is due to the strong interaction between graphene and the Pd substrate. Our findings point to the possibility of preparing semiconducting graphene layers for future carbon-based nanoelectronic devices via direct deposition onto strongly interacting substrates.
Collapse
Affiliation(s)
- Soon-Yong Kwon
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Prikhodko S, Sitzman S, Gambin V, Kodambaka S. In situ electron backscattered diffraction of individual GaAs nanowires. Ultramicroscopy 2008; 109:133-8. [DOI: 10.1016/j.ultramic.2008.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 07/11/2008] [Accepted: 09/12/2008] [Indexed: 10/21/2022]
|
9
|
Lordi V, Gambin V, Friedrich S, Funk T, Takizawa T, Uno K, Harris JS. Nearest-neighbor configuration in (GaIn)(NAs) probed by x-ray absorption spectroscopy. Phys Rev Lett 2003; 90:145505. [PMID: 12731929 DOI: 10.1103/physrevlett.90.145505] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2002] [Indexed: 05/24/2023]
Abstract
Ga(1-x)In(x)N(y)As(1-y) is a promising material system for the fabrication of inexpensive "last-mile" optoelectronic components. However, details of its atomic arrangement and the relationship to observed optical properties is not fully known. Particularly, a blueshift of emission wavelength is observed after annealing. In this work, we use x-ray absorption fine structure to study the chemical environment around N atoms in the material before and after annealing. We find that as-grown molecular beam epitaxy material consists of a nearly random distribution of atoms, while postannealed material shows segregation of In toward N. Ab initio simulations show that this short-range ordering creates a more thermodynamically stable alloy and is responsible for blueshifting the emission.
Collapse
Affiliation(s)
- Vincenzo Lordi
- Solid State and Photonics Laboratory, Stanford University, Stanford, California 94305, USA.
| | | | | | | | | | | | | |
Collapse
|