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Guo Y, Liu D, Miao C, Sun J, Pang Z, Wang P, Xu M, Han N, Yang ZX. Ambipolar transport in Ni-catalyzed InGaAs nanowire field-effect transistors for near-infrared photodetection. NANOTECHNOLOGY 2021; 32:145203. [PMID: 33443238 DOI: 10.1088/1361-6528/abd358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Weak n-type characteristics or poor p-type characteristics are limiting the applications of binary semiconductors based on ambipolar field-effect transistors (FETs). In this work, a ternary alloy of In0.2Ga0.8As nanowires (NWs) is successfully prepared using a Ni catalyst during a typical solid-source chemical-vapor-deposition process to balance the weak n-type conduction behavior in ambipolar GaAs NWFETs and the poor p-type conduction behavior in ambipolar InAs NWFETs. The presence of ambipolar transport, contributed by a native oxide shell and the body defects of the prepared In0.2Ga0.8As NWs, is confirmed by the constructed back-gated NWFETs. As demonstrated by photoluminescence, the bandgap of the prepared In0.2Ga0.8As NWs is 1.28 eV, offering the promise of application in near-infrared (NIR) photodetection. Under 850 nm laser illumination, the fabricated ambipolar NWFETs show extremely low dark currents of 50 pA and 0.5 pA when positive and negative gate voltages are applied, respectively. All the results demonstrate that with careful design of the surface oxide layer and the body defects, NWs are suitable for use in next-generation optoelectronic devices.
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Affiliation(s)
- Yanan Guo
- School of Microelectronics, School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, People's Republic of China
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Effect of the Uniaxial Compression on the GaAs Nanowire Solar Cell. MICROMACHINES 2020; 11:mi11060581. [PMID: 32532075 PMCID: PMC7345117 DOI: 10.3390/mi11060581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 11/16/2022]
Abstract
Research regarding ways to increase solar cell efficiency is in high demand. Mechanical deformation of a nanowire (NW) solar cell can improve its efficiency. Here, the effect of uniaxial compression on GaAs nanowire solar cells was studied via conductive atomic force microscopy (C-AFM) supported by numerical simulation. C-AFM I–V curves were measured for wurtzite p-GaAs NW grown on p-Si substrate. Numerical simulations were performed considering piezoresistance and piezoelectric effects. Solar cell efficiency reduction of 50% under a −0.5% strain was observed. The analysis demonstrated the presence of an additional fixed electrical charge at the NW/substrate interface, which was induced due to mismatch between the crystal lattices, thereby affecting the efficiency. Additionally, numerical simulations regarding the p-n GaAs NW solar cell under uniaxial compression were performed, showing that solar efficiency could be controlled by mechanical deformation and configuration of the wurtzite and zinc blende p-n segments in the NW. The relative solar efficiency was shown to be increased by 6.3% under −0.75% uniaxial compression. These findings demonstrate a way to increase efficiency of GaAs NW-based solar cells via uniaxial mechanical compression.
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Díaz Álvarez A, Peric N, Franchina Vergel NA, Nys JP, Berthe M, Patriarche G, Harmand JC, Caroff P, Plissard S, Ebert P, Xu T, Grandidier B. Importance of point defect reactions for the atomic-scale roughness of III-V nanowire sidewalls. NANOTECHNOLOGY 2019; 30:324002. [PMID: 30995632 DOI: 10.1088/1361-6528/ab1a4e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The surface morphology of III-V semiconductor nanowires (NWs) protected by an arsenic cap and subsequently evaporated in ultrahigh vacuum is investigated with scanning tunneling microscopy and scanning transmission electron microscopy. We show that the changes of the surface morphology as a function of the NW composition and the nature of the seed particles are intimately related to the formation and reaction of surface point defects. Langmuir evaporation close to the congruent evaporation temperature causes the formation of vacancies which nucleate and form vacancy islands on {110} sidewalls of self-catalyzed InAs NWs. However, for annealing temperatures much smaller than the congruent temperature, a new phenomenon occurs: group III vacancies form and are filled by excess As atoms, leading to surface AsGa antisites. The resulting Ga adatoms nucleate with excess As atoms at the NW edges, producing monoatomic-step islands on the {110} sidewalls of GaAs NWs. Finally, when gold atoms diffuse from the seed particle onto the {110} sidewalls during evaporation of the protective As cap, Langmuir evaporation does not take place, leaving the sidewalls of InAsSb NWs atomically flat.
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Affiliation(s)
- Adrian Díaz Álvarez
- Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520-IEMN, F-59000 Lille, France
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Alekseev PA, Sharov VA, Dunaevskiy MS, Kirilenko DA, Ilkiv IV, Reznik RR, Cirlin GE, Berkovits VL. Control of Conductivity of In xGa 1-xAs Nanowires by Applied Tension and Surface States. NANO LETTERS 2019; 19:4463-4469. [PMID: 31203633 DOI: 10.1021/acs.nanolett.9b01264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electronic properties of semiconductor AIIIBV nanowires (NWs) due to their high surface/volume ratio can be effectively controlled by NW strain and surface electronic states. We study the effect of applied tension on the conductivity of wurtzite InxGa1-xAs (x ∼ 0.8) NWs. Experimentally, conductive atomic force microscopy is used to measure the I-V curves of vertically standing NWs covered by native oxide. To apply tension, the microscope probe touching the NW side is shifted laterally to produce a tensile strain in the NW. The NW strain significantly increases the forward current in the measured I-V curves. When the strain reaches 4%, the I-V curve becomes almost linear, and the forward current increases by 3 orders of magnitude. In the latter case, the tensile strain is supposed to shift the conduction band minima below the Fermi level, whose position, in turn, is fixed by surface states. Consequently, the surface conductivity channel appears. The observed effects confirm that the excess surface arsenic is responsible for the Fermi level pinning at oxidized surfaces of III-As NWs.
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Affiliation(s)
| | - Vladislav A Sharov
- Ioffe Institute , Saint Petersburg 194021 , Russia
- Saint-Petersburg Academic University , Saint Petersburg 194021 , Russia
| | | | | | - Igor V Ilkiv
- Saint-Petersburg Academic University , Saint Petersburg 194021 , Russia
| | | | - George E Cirlin
- Saint-Petersburg Academic University , Saint Petersburg 194021 , Russia
- ITMO University , Saint Petersburg 197101 , Russia
- Saint Petersburg Electrotechnical University LETI , Saint Petersburg 197376 , Russia
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Abstract
Solar energy is abundant, clean, and renewable, making it an ideal energy source. Solar cells are a good option to harvest this energy. However, it is difficult to balance the cost and efficiency of traditional thin-film solar cells, whereas nanowires (NW) are far superior in making high-efficiency low-cost solar cells. Therefore, the NW solar cell has attracted great attention in recent years and is developing rapidly. Here, we review the great advantages, recent breakthroughs, novel designs, and remaining challenges of NW solar cells. Special attention is given to (but not limited to) the popular semiconductor NWs for solar cells, in particular, Si, GaAs(P), and InP.
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Zhang Y, Sanchez AM, Aagesen M, Huo S, Fonseka HA, Gott JA, Kim D, Yu X, Chen X, Xu J, Li T, Zeng H, Boras G, Liu H. Growth and Fabrication of High-Quality Single Nanowire Devices with Radial p-i-n Junctions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1803684. [PMID: 30556282 DOI: 10.1002/smll.201803684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Nanowires (NWs) with radial p-i-n junction have advantages, such as large junction area and small influence from the surface states, which can lead to highly efficient material use and good device quantum efficiency. However, it is difficult to make high-quality core-shell NW devices, especially single NW devices. Here, the key factors during the growth and fabrication process that influence the quality of single core-shell p-i-n NW devices are studied using GaAs(P) NW photovoltaics as an example. By p-doping and annealing, good ohmic contact is achieved on NWs with a diameter as small as 50-60 nm. Single NW photovoltaics are subsequently developed and a record fill factor of 80.5% is shown. These results bring valuable information for making single NW devices, which can further benefit the development of high-density integration circuits.
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Affiliation(s)
- Yunyan Zhang
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Ana M Sanchez
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Martin Aagesen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark
| | - Suguo Huo
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - H Aruni Fonseka
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - James A Gott
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Dongyoung Kim
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Xuezhe Yu
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Xingyou Chen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Jia Xu
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Tianyi Li
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Haotian Zeng
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Giorgos Boras
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
| | - Huiyun Liu
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
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