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Title: Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels

Abstract

We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightlymore » decreasing the exciton band intensity.« less

Authors:
 [1];  [2];  [2];  [2];  [2];  [1];  [2]
  1. National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA
  2. National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1326326
Report Number(s):
NREL/JA-5K00-66565
Journal ID: ISSN 0021-8979
DOE Contract Number:
AC36-08GO28308
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; catholuminescence; excitons; II-VI semiconductors; geographic information systems; dislocations

Citation Formats

Moseley, John, Al-Jassim, Mowafak M., Guthrey, Harvey L., Burst, James M., Duenow, Joel N., Ahrenkiel, Richard K., and Metzger, Wyatt K. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels. United States: N. p., 2016. Web. doi:10.1063/1.4962286.
Moseley, John, Al-Jassim, Mowafak M., Guthrey, Harvey L., Burst, James M., Duenow, Joel N., Ahrenkiel, Richard K., & Metzger, Wyatt K. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels. United States. doi:10.1063/1.4962286.
Moseley, John, Al-Jassim, Mowafak M., Guthrey, Harvey L., Burst, James M., Duenow, Joel N., Ahrenkiel, Richard K., and Metzger, Wyatt K. Fri . "Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels". United States. doi:10.1063/1.4962286.
@article{osti_1326326,
title = {Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels},
author = {Moseley, John and Al-Jassim, Mowafak M. and Guthrey, Harvey L. and Burst, James M. and Duenow, Joel N. and Ahrenkiel, Richard K. and Metzger, Wyatt K.},
abstractNote = {We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightly decreasing the exciton band intensity.},
doi = {10.1063/1.4962286},
journal = {Journal of Applied Physics},
number = 10,
volume = 120,
place = {United States},
year = {Fri Sep 09 00:00:00 EDT 2016},
month = {Fri Sep 09 00:00:00 EDT 2016}
}