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Title: Deep level defects in dilute GaAsBi alloys grown under intense UV illumination

Abstract

Dilute GaAs1-xBix alloys exhibiting narrow band edge photoluminescence (PL) were recently grown by molecular beam epitaxy (MBE) with the growth surface illuminated by intense UV radiation. To investigate whether the improved optical quality of these films results from a reduction in the concentration of deep level defects, p+/n and n+/p junction diodes were fabricated on both the illuminated and dark areas of several samples. Deep Level Transient Spectroscopy (DLTS) measurements show that the illuminated and dark areas of both the n- and p-type GaAs1-xBix epi-layers have similar concentrations of near mid-gap electron and hole traps, in the 1015 cm-3 range. Thus the improved PL spectra cannot be explained by a reduction in non-radiative recombination at deep level defects. We note that carrier freeze-out above 35 K is significantly reduced in the illuminated areas of the p-type GaAs1-xBix layers compared to the dark areas, allowing the first DLTS measurements of defect energy levels close to the valence band edge. These defect levels may account for differences in the PL spectra from the illuminated and dark areas of un-doped layers with a similar Bi fraction.

Authors:
; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1329997
Report Number(s):
NREL/JA-5K00-67319
Journal ID: ISSN 0268-1242
DOE Contract Number:
AC36-08GO28308
Resource Type:
Journal Article
Resource Relation:
Journal Name: Semiconductor Science and Technology; Journal Volume: 31; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GaAsBi; DLTS; deep level defects

Citation Formats

Mooney, P. M., Tarun, Marianne, Beaton, D. A., Mascarenhas, A., and Alberi, K. Deep level defects in dilute GaAsBi alloys grown under intense UV illumination. United States: N. p., 2016. Web. doi:10.1088/0268-1242/31/8/085014.
Mooney, P. M., Tarun, Marianne, Beaton, D. A., Mascarenhas, A., & Alberi, K. Deep level defects in dilute GaAsBi alloys grown under intense UV illumination. United States. doi:10.1088/0268-1242/31/8/085014.
Mooney, P. M., Tarun, Marianne, Beaton, D. A., Mascarenhas, A., and Alberi, K. 2016. "Deep level defects in dilute GaAsBi alloys grown under intense UV illumination". United States. doi:10.1088/0268-1242/31/8/085014.
@article{osti_1329997,
title = {Deep level defects in dilute GaAsBi alloys grown under intense UV illumination},
author = {Mooney, P. M. and Tarun, Marianne and Beaton, D. A. and Mascarenhas, A. and Alberi, K.},
abstractNote = {Dilute GaAs1-xBix alloys exhibiting narrow band edge photoluminescence (PL) were recently grown by molecular beam epitaxy (MBE) with the growth surface illuminated by intense UV radiation. To investigate whether the improved optical quality of these films results from a reduction in the concentration of deep level defects, p+/n and n+/p junction diodes were fabricated on both the illuminated and dark areas of several samples. Deep Level Transient Spectroscopy (DLTS) measurements show that the illuminated and dark areas of both the n- and p-type GaAs1-xBix epi-layers have similar concentrations of near mid-gap electron and hole traps, in the 1015 cm-3 range. Thus the improved PL spectra cannot be explained by a reduction in non-radiative recombination at deep level defects. We note that carrier freeze-out above 35 K is significantly reduced in the illuminated areas of the p-type GaAs1-xBix layers compared to the dark areas, allowing the first DLTS measurements of defect energy levels close to the valence band edge. These defect levels may account for differences in the PL spectra from the illuminated and dark areas of un-doped layers with a similar Bi fraction.},
doi = {10.1088/0268-1242/31/8/085014},
journal = {Semiconductor Science and Technology},
number = 8,
volume = 31,
place = {United States},
year = 2016,
month = 7
}
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