GRAIN-BOUNDARY EFFECTS IN THE EBIC RESPONSE OF THIN-FILM SOLAR-CELLS

The diffusion length of minority carriers in a CdS-CdTe thin film polycrystalline junction device was measured using Electron Beam Induced Current. The EBIC response did not resemble the approximately exponential shape predicted by current theory. Rather it consisted of a broad region located approximately at the junction but consisting of multiple peaks and notched tails. Accordingly, a general model of the EBIC response was developed which takes into account surface recombination, finite generation volume, and grain boundary recombination to account for the features seen in the data. The important role of grain boundary recombination velocity can be seen in the model. © 1990.