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

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 (V-OC) 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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4722921]