Photomemory in CdTe thin-film solar cells

It is shown that a change in the chemisorption equilibrium on the crystallite boundaries in thin-film photoconverters based on polycrystalline CdTe occurs when they are subjected to radiation. This leads to the appearance of photomemory as a result of a change in the surface potential and a corresponding change in the surface recombination rate. This effect may be the reason for the instability of the parameters of polycrystalline solar cells and can lead to a degradation and to an enhancement of the photoconversion efficiency. An experimental technique, which allows one to determine the dominant type of surface state at the boundaries of the crystallites, is considered. (C) 1999 American Institute of Physics. [S1063-7826(99)02004-9].