Gradients of Be-dopant concentration in self-catalyzed GaAs nanowires

Author(s)

Piton, Marcelo Rizzo ^{[1, 2]} ; Koivusalo, Eero ^[2] ; Hakkarainen, Teemu ^[2] ; Avanco Galeti, Helder Vinicius ^[3] ; Rodrigues, Ariano De Giovanni ^[1] ; Talmila, Soile ^[2] ; Souto, Sergio ^[4] ; Lupo, Donald ^[5] ; Gobato, Yara Galvao ^{[1, 6]} ; Guina, Mircea ^[2]

Affiliation

^[1] Univ Fed Sao Carlos, Phys Dept, Sao Carlos, SP - Brazil

^[2] Tampere Univ, Optoelect Res Ctr, Phys Unit, Tampere - Finland

^[3] Univ Fed Sao Carlos, Elect Engn Dept, Sao Carlos, SP - Brazil

^[4] Univ Sao Paulo, FZEA ZAB, Pirassununga, SP - Brazil

^[5] Tampere Univ, Elect & Commun Engn, Tampere - Finland

^[6] Radboud Univ Nijmegen, High Field Magnet Lab, Nijmegen - Netherlands

• Document type: Journal article
• Source: Nanotechnology; v. 30, n. 33 AUG 16 2019.
• Web of Science Citations: 1

Abstract

Effective and controllable doping is instrumental for enabling the use of III-V semiconductor nanowires (NWs) in practical electronics and optoelectronics applications. To this end, dopants are incorporated during self-catalyzed growth via vapor-liquid-solid mechanism through the catalyst droplet or by vapor-solid mechanism of the sidewall growth. The interplay of these mechanisms together with the competition between axial elongation and radial growth of NWs can result in dopant concentration gradients along the NW axis. Here, we report an investigation of Be-doped p-type GaAs NWs grown by the self-catalyzed method on lithography-free Si/SiOx templates. The influence of dopant incorporation on the structural properties of the NWs is analyzed by scanning and transmission electron microscopy. By combining spatially resolved Raman spectroscopy and transport characterization, we are able to estimate the carrier concentration, mobility and resistivity on single-NW level. We show that Be dopants are incorporated predominantly by vapor-solid mechanism for low Be flux, while the relative contribution of vapor-liquid-solid incorporation is increased for higher Be flux, resulting in axial dopant gradients that depend on the nominal doping level. (AU)

• FAPESP's process: 14/50513-7 - Tailoring the transport and optical properties if III-Bi-V nanostructures for advanced photonic devices
• Grantee: Helder Vinícius Avanço Galeti
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/01808-5 - Optical and Transport Properties in High Magnetic Fields of Semiconductor Heterostructures and Devices based on Two Dimensional Materials
• Grantee: Yara Galvão Gobato
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 16/10668-7 - Optical and Transport Properties of two-dimensional semicondutors based on transition metal dichalcogenides
• Grantee: Yara Galvão Gobato
• Support Opportunities: Regular Research Grants