Thin metal oxide films to modify a window layer in CdTe-based solar cells for improved performance

Abstract

We report on CdS/CdTe photovoltaic devices containing a thin Ta2O5 film deposited onto the CdS window layer. For thicknesses below 5 nm, Ta2O5 films between CdS and CdTe improve the solar cell performance despite the insulating nature of the interlayer material. Using the Ta2O5 interlayer, an open circuit voltage (VOC) gain of over 100 mV was demonstrated compared to a CdTe/CdS baseline. A Ta2O5 interlayer enabled the fabrication of CdTe solar cells with extremely thin (less than 30 nm) CdS layers. The efficiency of these cells exceeded that of a base line cell with 95 nm of CdS.