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Ramaswamy P, Devkota S, Pokharel R, Nalamati S, Stevie F, Jones K, Reynolds L, Iyer S. A study of dopant incorporation in Te-doped GaAsSb nanowires using a combination of XPS/UPS, and C-AFM/SKPM. Sci Rep 2021; 11:8329. [PMID: 33859310 PMCID: PMC8050051 DOI: 10.1038/s41598-021-87825-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/31/2021] [Indexed: 11/09/2022] Open
Abstract
We report the first study on doping assessment in Te-doped GaAsSb nanowires (NWs) with variation in Gallium Telluride (GaTe) cell temperature, using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), conductive-atomic force microscopy (C-AFM), and scanning Kelvin probe microscopy (SKPM). The NWs were grown using Ga-assisted molecular beam epitaxy with a GaTe captive source as the dopant cell. Te-incorporation in the NWs was associated with a positive shift in the binding energy of the 3d shells of the core constituent elements in doped NWs in the XPS spectra, a lowering of the work function in doped NWs relative to undoped ones from UPS spectra, a significantly higher photoresponse in C-AFM and an increase in surface potential of doped NWs observed in SKPM relative to undoped ones. The carrier concentration of Te-doped GaAsSb NWs determined from UPS spectra are found to be consistent with the values obtained from simulated I–V characteristics. Thus, these surface analytical tools, XPS/UPS and C-AFM/SKPM, that do not require any sample preparation are found to be powerful characterization techniques to analyze the dopant incorporation and carrier density in homogeneously doped NWs.
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Affiliation(s)
- Priyanka Ramaswamy
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC, 27401, USA
| | - Shisir Devkota
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC, 27401, USA
| | - Rabin Pokharel
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC, 27401, USA
| | - Surya Nalamati
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC, 27401, USA
| | - Fred Stevie
- Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC, 27695, USA
| | - Keith Jones
- Asylum Research, an Oxford Instruments Company, 6310 Hollister Ave., Santa Barbara, CA, 93117, USA
| | - Lew Reynolds
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Shanthi Iyer
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC, 27401, USA.
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Barnett CJ, Jackson G, Jones DR, Lewis AR, Welsby K, Evans JE, McGettrick JD, Watson T, Maffeis TGG, Dunstan PR, Barron AR, Cobley RJ. Investigation into the effects of surface stripping ZnO nanosheets. NANOTECHNOLOGY 2018; 29:165701. [PMID: 29425112 DOI: 10.1088/1361-6528/aaae5c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
ZnO nanosheets are polycrystalline nanostructures that are used in devices including solar cells and gas sensors. However, for efficient and reproducible device operation and contact behaviour the conductivity characteristics must be controlled and surface contaminants removed. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanosheets altering the contact type from near-ohmic to rectifying by removing the donor-type defects, which photoluminescence shows to be concentrated in the near-surface. Controlled doses of argon treatments allow nanosheets to be customised for device formation.
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Affiliation(s)
- Chris J Barnett
- Energy Safety Research Institute, Swansea University, Bay Campus, Swansea SA1 8EN, United Kingdom
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