Electronic defects in Cu ( In , Ga ) S e 2 : Towards a comprehensive model
2019; American Physical Society; Volume: 3; Issue: 9 Linguagem: Inglês
10.1103/physrevmaterials.3.090302
ISSN2476-0455
AutoresConrad Spindler, Finn Babbe, Max Hilaire Wolter, Florian Ehré, Korra Santhosh, Pit Hilgert, Florian Werner, Susanne Siebentritt,
Tópico(s)Semiconductor materials and interfaces
ResumoChalcopyrite materials, like CuInSe2 or Cu(In,Ga)Se2, are used as absorbers in thin film solar cells. The interest in thin film solar cells is based on the fact that they present a particularly low carbon footprint. However, much less is known about the electronic defects in the material compared to more common semiconductors. The authors use mainly photoluminescence to study the electronic defects. In this paper they review experimental and theoretical defect studies and arrive at a comprehensive model. They show that the shallow defects, that contribute free carriers, can be identified from low temperature photoluminescence spectroscopy. Deep defects, which are detrimental to the solar cell, are also known to exist and are observed in capacitance spectroscopy but are difficult to observe in photoluminescence. The authors demonstrate that by a careful investigation of the composition dependence and the temperature dependence of the luminescence spectra, they can actually identify two deep defects in Cu(In,Ga)Se2: one is at least partly responsible for the efficiency loss of wide bandgap chalcopyrite solar cells, the other one could be responsible for the lower efficiency of Cu-rich material.
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