Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors

The relatively small band gap values (~1 eV) of CuInSe2 thin films limit the conversion efficiencies of completed CuInSe2/CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to homogeneously increase the band gap by substituting indiu...

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Main Author: Francis B. Dejene
Format: Article
Language:English
Published: Wiley 2014-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2014/361652
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author Francis B. Dejene
author_facet Francis B. Dejene
author_sort Francis B. Dejene
collection DOAJ
description The relatively small band gap values (~1 eV) of CuInSe2 thin films limit the conversion efficiencies of completed CuInSe2/CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to homogeneously increase the band gap by substituting indium with gallium. In this study, thermal evaporation of InSe/Cu/Gase precursors was exposed to an elemental Se vapour under defined conditions. This technique produced large-grained, single-phase Cu(In,Ga)Se2 thin films with a high degree of in-depth compositional uniformity. The selenization temperature, ramp time, reaction period, and the effusion cell temperature with respect to the Cu(In,Ga)Se2 films were optimized in this study. The homogeneous incorporation of Ga into CuInSe2 led to a systematic shift in the lattice spacing parameters and band gap of the absorber films. Under optimized conditions, gallium in cooperation resulted only in a marginal decrease in the grain size, X-ray diffraction studies confirmed single-phase Cu(In,Ga)Se2 material, and X-ray photoluminescence spectroscopy in-depth profiling revealed a uniform distribution of the elements through the entire depth of the alloy. From these studies optimum selenization conditions were determined for the deposition of homogeneous Cu(In,Ga)Se2 thin films with optimum band gap values between 1.01 and 1.21 eV.
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spelling doaj-art-cb6437607652470aad274bf9653ae8332025-02-03T05:48:09ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422014-01-01201410.1155/2014/361652361652Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe PrecursorsFrancis B. Dejene0Department of Physics, University of the Free State, Private Bag X13, Phuthaditjhaba 9866, South AfricaThe relatively small band gap values (~1 eV) of CuInSe2 thin films limit the conversion efficiencies of completed CuInSe2/CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to homogeneously increase the band gap by substituting indium with gallium. In this study, thermal evaporation of InSe/Cu/Gase precursors was exposed to an elemental Se vapour under defined conditions. This technique produced large-grained, single-phase Cu(In,Ga)Se2 thin films with a high degree of in-depth compositional uniformity. The selenization temperature, ramp time, reaction period, and the effusion cell temperature with respect to the Cu(In,Ga)Se2 films were optimized in this study. The homogeneous incorporation of Ga into CuInSe2 led to a systematic shift in the lattice spacing parameters and band gap of the absorber films. Under optimized conditions, gallium in cooperation resulted only in a marginal decrease in the grain size, X-ray diffraction studies confirmed single-phase Cu(In,Ga)Se2 material, and X-ray photoluminescence spectroscopy in-depth profiling revealed a uniform distribution of the elements through the entire depth of the alloy. From these studies optimum selenization conditions were determined for the deposition of homogeneous Cu(In,Ga)Se2 thin films with optimum band gap values between 1.01 and 1.21 eV.http://dx.doi.org/10.1155/2014/361652
spellingShingle Francis B. Dejene
Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
Advances in Materials Science and Engineering
title Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
title_full Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
title_fullStr Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
title_full_unstemmed Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
title_short Morphological, Structural, and Optical Properties of Single-Phase Cu(In,Ga)Se2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors
title_sort morphological structural and optical properties of single phase cu in ga se2 thin films from the selenization of thermally evaporated inse cu gase precursors
url http://dx.doi.org/10.1155/2014/361652
work_keys_str_mv AT francisbdejene morphologicalstructuralandopticalpropertiesofsinglephasecuingase2thinfilmsfromtheselenizationofthermallyevaporatedinsecugaseprecursors