Nanoscale photovoltaic performance in micro/nanopatterned CdTe-CdS thin film solar cells

A new approach to measure the local response of micropatterned CdTe based solar cells is presented. This method provides fast results with high spatial resolution and the ability to map short circuit current (Ish), open circuit voltage (Voc), maximum power, and fill factor. It is based on consecutive photoconductive atomic force microscopy (pcAFM) scans collected at different DC biases over the same area. An array of I-V response curves results based on spectra for any given location (image pixel) according to the photoresponse (pcAFM current contrast) as a function of the applied bias (image). Grains, grain boundaries and even twin boundaries are clearly resolved.