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Se activity and its effect on Cu(In,Ga)Se 2 photovoltaic thin films
Author(s) -
Contreras Miguel A.,
Repins Ingrid,
Metzger Wyatt K.,
Romero Manuel,
AbouRas Daniel
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200881243
Subject(s) - materials science , thin film , photoluminescence , microstructure , grain boundary , evaporation , solar cell , cathode , stoichiometry , luminescence , optoelectronics , analytical chemistry (journal) , composite material , nanotechnology , chemistry , chromatography , physics , thermodynamics
We study some physical properties of CuIn 1– x Ga x Se 2 thin‐films fabricated by evaporation from elemental sources under various Selenium environments. Specifically, thin‐films were fabricated under growth conditions such as Se deficiency, near stoichiometry and excess Se during coevaporation to investigate the impact of the Se environment on absorber film properties and ultimately the device performance. We determine the chemical activity of Se in the evaporation process has a strong influence on film macrostructure (prefered orientation) and microstructure, particularly at the grain and grain boundary level. It is shown that the optoelectronic properties at grain boundaries are affected by the Se environment used resulting in absorber thin‐films with distictive defect distribution and defect density. Consequently, the performance of the solar cells fabricated from those films is also affected by the Se environment. These effects on solar cell performance and absorber properties are reported in a (i) structural analysis of the CuIn 1– x Ga x Se 2 /Mo/glass samples by X‐ray and electron backscattering techniques; (ii) optolectronic radiative characteristics of the absorbers by cathode luminescence and photoluminescence studies and (iii) current–voltage, quantum efficiency and capacitance–voltage measurements for the solar cells made from the absorbers fabricated under the pre prescribed Se growth conditions. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)