Review of CdTe1-xSex thin films in solar cell applications

Abstract

Recent improvements in CdTe thin film solar cells have been achieved by using CdTe1-xSex as a part of the absorber layer. This review summarizes the published literature concerning the material properties of CdTe1-xSex and its application in current thin film CdTe photovoltaics. One of the important properties of CdTe1-xSex is its band gap bowing, which facilitates a lowering of the CdTe band gap towards the optimum band gap for highest theoretical efficiency. In practice, a CdTe1-xSex gradient is introduced to the front of CdTe, which induces a band gap gradient and allows for the fabrication of solar cells with enhanced short-circuit current while maintaining a high open-circuit voltage. In some device structures, the addition of CdTe1-xSex also allows for a reduction in CdS thickness or its complete elimination, reducing parasitic absorption of low wavelength photons.