A study of the effects of post-deposition treatments on CdS/CdTe thin film solar cells using high resolution optical beam induced current

The optical beam induced current (OBIC) technique was applied using a scanning optical microscope (SOM) to study n-Cds/p-CdTe thin film solar cells which had been subjected to different post-deposition treatments. High spatial resolution maps were obtained of the current collection with and without an applied reverse bias. The quantum efficiency of the devices was also measured with high spatial resolution. The results both quantify and illustrate vividly the manner in which the well known CdCl2 treatment increases collection efficiency. The high uniformity in the best cells indicates that grain boundaries do not play a substantial role in limiting collection efficiency.