First-Principles Study of Energy Band Alignment in Pristine CdTe/TeO2/Te Interfaces

A first-principles atomistic modeling approach is utilized to investigate the critical factors responsible for electronic structure and charge transport phenomena within back heterointerfacial regions of cadmium telluride thin-film photovoltaic devices. Within CdTe PV, the absorber/back contact interface is a major limiting factor to solar cell device performance and energy conversion efficiencies, even with a tellurium back contact layer present. It is speculated that a natively-forming tellurium dioxide layer could passivate the CdTe back interface prior to Te deposition and contribute to achieving higher device efficiencies. However, there is not a clear fundamental understanding of how atomic-scale properties at the CdTe/TeO2 and TeO
2
/Te heterointerfaces based on plane orientation modify the charge transport behaviors in the PV device as a whole. This study addresses the gap in knowledge of CdTe-based absorber/back contact interfacial effects by computationally describing electronic structures of pristine CdTe/TeO
2
/Te heterointerfaces and providing insight on efficient pathways for interface engineering in CdTe-based thin-film PV applications.