Title: Doping concentration dependence of the photoluminescence spectra of n-type GaAs nanowires

Abstract

In this work, the photoluminescence spectra of n-type doped GaAs nanowires, grown by the metal organic chemical vapor deposition method, are measured at 4K and 77 K. Our measurements indicate that an increase in carrier concentration leads to an increase in the complexity of the doping mechanism, which we attribute to the formation of different recombination centers. At high carrier concentrations, we observe a blueshift of the effective band gap energies by up to 25 meV due to the Burstein-Moss shift. Based on the full width at half maximum (FWHM) of the photoluminescence peaks, we estimate the carrier concentrations for these nanowires, which varies from 6 x 10¹⁷ cm^-3 (lightly doped), to 1.5 x 10¹⁸ cm^-3 (moderately doped), to 3.5 x 10¹⁸ cm^-3 (heavily doped) as the partial pressure of the disilane is varied from 0.01 sccm to 1 sccm during the growth process. We find that the growth temperature variation does not affect the radiative recombination mechanism; however, it does lead to a slight enhancement in the optical emission intensities. For GaAs nanowire arrays measured at room temperature, we observe the same general dependence of band gap, FWHM, and carrier concentration on doping.

Authors:

Arab, Shermin ^[1]; Yao, Maoqing ^[1]; Zhou, Chongwu ^[2]; Daniel Dapkus, P. ^[3]; Cronin, Stephen B. ^[2]

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+ Show Author Affiliations

1. Univ. of Southern California, Los Angeles, CA (United States). Center for Energy Nanoscience and Dept. of Electrical Engineering
2. Univ. of Southern California, Los Angeles, CA (United States). Center for Energy Nanoscience, Dept. of Chemical Engineering and Materials Science and Dept. of Electrical Engineering
3. Univ. of Southern California, Los Angeles, CA (United States). Center for Energy Nanoscience, Dept. of Chemical Engineering and Materials Science, Dept. of Physics and Dept. of Electrical Engineering

Publication Date:

Fri May 06 00:00:00 EDT 2016

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Energy Nanoscience (CEN); Univ. of Southern California, Los Angeles, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1470769

Alternate Identifier(s):

OSTI ID: 1251438

Grant/Contract Number:  

SC0001013

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 108; Journal Issue: 18; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE; semiconductors; band gap; photoluminescence spectroscopy; Hall effect; nanowires; chemical elements; silicon compounds; doping; phonons; chemical vapor deposition