Thin Film Partnership Program

reproducibility of device efficiency and stability has been demonstrated during long duration operation of the system with a single charge loading for the CdS, CdTe and CdCl2 process. In order to advance back contact processing, a significant upgrade to increase the processing space in our pilot scale system has been designed, fabricated and has been installed. A series of detailed studies on the effect of oxygen during the CdCl2 treatment has been performed. Oxygen has been shown to improve the effectiveness of the CdCl2 treatment. Mathematical modeling of a package design has yielded results that show that moisture can be kept from our device for 22 years at 65C temperature with saturated humidity. Hardware to perform steady state photocapacitance (PHCAP) has been designed, built and tested in our laboratory. The effect of processing on the deep states in CdTe devices can be seen quantitatively. Optimum process conditions lead to lower photocapacitance signals. The feasibility of cooling the substrate in vacuum for optimum processing of the back contact has been demonstrated. A large number of experiments have been performed on laser scribing of CdS/CdTe films. Mechanical scribing has yielded the lowest contact resistance between the scribed region and the metallization, to date. Researchers at National Starch and Chemicals (NSC) have performed many experiments t