A study of n-doping in self-catalyzed GaAsSb nanowires using GaTe dopant source and ensemble nanowire near-infrared photodetector

Shisir Devkota; Mehul Parakh; Sean Johnson; Priyanka Ramaswamy; Michael Lowe; Aubrey Penn; Lew Reynolds; Shanthi Iyer

doi:10.1088/1361-6528/abb506

A study of n-doping in self-catalyzed GaAsSb nanowires using GaTe dopant source and ensemble nanowire near-infrared photodetector

Nanotechnology. 2020 Dec 11;31(50):505203. doi: 10.1088/1361-6528/abb506.

Authors

Shisir Devkota¹, Mehul Parakh¹, Sean Johnson², Priyanka Ramaswamy², Michael Lowe², Aubrey Penn^{3

4}, Lew Reynolds⁴, Shanthi Iyer¹

Affiliations

¹ Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America.
² Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411, United States of America.
³ Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, United States of America.
⁴ Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695, United States of America.

PMID: 33021209
DOI: 10.1088/1361-6528/abb506

Abstract

This work reports a comprehensive investigation of the effect of gallium telluride (GaTe) cell temperature variation (T_GaTe) on the morphological, optical, and electrical properties of doped-GaAsSb nanowires (NWs) grown by Ga-assisted molecular beam epitaxy (MBE). These studies led to an optimum doping temperature of 550 °C for the growth of tellurium (Te)-doped GaAsSb NWs with the best optoelectronic and structural properties. Te incorporation resulted in a decrease in the aspect ratio of the NWs causing an increase in the Raman longitudinal optical/transverse optical vibrational mode intensity ratio, large photoluminescence emission with an exponential decay tail on the high energy side, promoting tunnel-assisted current conduction in ensemble NWs and significant photocurrent enhancement in the single nanowire. A Schottky barrier photodetector (PD) using Te-doped ensemble NWs with broad spectral range and a longer wavelength cutoff at ∼1.2 µm was demonstrated. These PDs exhibited responsivity in the range of 580-620 A W^-1 and detectivity of 1.2-3.8 × 10¹² Jones. The doped GaAsSb NWs have the potential for further improvement, paving the path for high-performance near-infrared (NIR) photodetection applications.