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

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 10 17 cm -3 (lightly doped), to 1.5 x 10 18 cm -3 (moderately doped), to 3.5 x 10 18 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:
 [1] ;  [1] ;  [2] ;  [3] ;  [2]
  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:
Grant/Contract Number:
SC0001013
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)
Research Org:
Univ. of Southern California, Los Angeles, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
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
OSTI Identifier:
1470769
Alternate Identifier(s):
OSTI ID: 1251438