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Title: Optical and Structural Properties of High-Efficiency Epitaxial Cu(In,Ga)Se 2 Grown on GaAs

Abstract

Photovoltaic devices based on Cu(In,Ga)Se 2 (CIGS) usually employ polycrystalline thin films as the absorber layer. This is because, to date, the highest conversion efficiencies have been attained with polycrystalline CIGS films. Recently, Nishinaga et al. presented an epitaxial CIGS thin-film solar cell grown on a GaAs (100) substrate with a conversion efficiency of 20.0%. In this contribution, we study the optical and structural properties of this high-efficiency epitaxial film, along with others with different compositions using cathodoluminescence spectrum imaging and transmission electron microscopy. A comparison of the high-efficiency epitaxial film and a traditional polycrystalline film with a similar global composition reveals significant differences in microstructure and uniformity of emission properties despite similar performance. The analysis of epitaxial films with a higher gallium concentration indicates that the emission characteristics and nature of extended defects in epitaxial CIGS films are strongly dependent on the gallium content. The results presented here provide evidence that, with further optimization, photovoltaic conversion efficiencies of epitaxial CIGS films could exceed those of polycrystalline CIGS.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [2];  [1];  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Inst. of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
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:
1592394
Report Number(s):
NREL/JA-5K00-72576
Journal ID: ISSN 1944-8244
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 12; Journal Issue: 2; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; epitaxial CIGS; cathodoluminescence; solar cell; defect characterization; TEM; CIGS microscopy

Citation Formats

Guthrey, Harvey L., Norman, Andrew, Nishinaga, Jiro, Niki, Shigeru, Al-Jassim, Mowafak M., and Shibata, Hajime. Optical and Structural Properties of High-Efficiency Epitaxial Cu(In,Ga)Se2 Grown on GaAs. United States: N. p., 2019. Web. doi:10.1021/acsami.9b18040.
Guthrey, Harvey L., Norman, Andrew, Nishinaga, Jiro, Niki, Shigeru, Al-Jassim, Mowafak M., & Shibata, Hajime. Optical and Structural Properties of High-Efficiency Epitaxial Cu(In,Ga)Se2 Grown on GaAs. United States. doi:10.1021/acsami.9b18040.
Guthrey, Harvey L., Norman, Andrew, Nishinaga, Jiro, Niki, Shigeru, Al-Jassim, Mowafak M., and Shibata, Hajime. Tue . "Optical and Structural Properties of High-Efficiency Epitaxial Cu(In,Ga)Se2 Grown on GaAs". United States. doi:10.1021/acsami.9b18040.
@article{osti_1592394,
title = {Optical and Structural Properties of High-Efficiency Epitaxial Cu(In,Ga)Se2 Grown on GaAs},
author = {Guthrey, Harvey L. and Norman, Andrew and Nishinaga, Jiro and Niki, Shigeru and Al-Jassim, Mowafak M. and Shibata, Hajime},
abstractNote = {Photovoltaic devices based on Cu(In,Ga)Se2 (CIGS) usually employ polycrystalline thin films as the absorber layer. This is because, to date, the highest conversion efficiencies have been attained with polycrystalline CIGS films. Recently, Nishinaga et al. presented an epitaxial CIGS thin-film solar cell grown on a GaAs (100) substrate with a conversion efficiency of 20.0%. In this contribution, we study the optical and structural properties of this high-efficiency epitaxial film, along with others with different compositions using cathodoluminescence spectrum imaging and transmission electron microscopy. A comparison of the high-efficiency epitaxial film and a traditional polycrystalline film with a similar global composition reveals significant differences in microstructure and uniformity of emission properties despite similar performance. The analysis of epitaxial films with a higher gallium concentration indicates that the emission characteristics and nature of extended defects in epitaxial CIGS films are strongly dependent on the gallium content. The results presented here provide evidence that, with further optimization, photovoltaic conversion efficiencies of epitaxial CIGS films could exceed those of polycrystalline CIGS.},
doi = {10.1021/acsami.9b18040},
journal = {ACS Applied Materials and Interfaces},
issn = {1944-8244},
number = 2,
volume = 12,
place = {United States},
year = {2019},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 10, 2020
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