Dependence of charge collection in thin-film CdTe solar cells on the absorber layer parameters

Charge collection efficiency in thin-film CdS/CdTe solar cells is discussed taking into consideration losses caused by a finite thickness of the p-CdTe layer, as well as recombination losses at the front and back surfaces. The dependences of the drift and diffusion components of the short-circuit current on the uncompensated acceptor concentration, charge carrier lifetime, recombination velocities at the CdS–CdTe interface and the back surface of the CdTe layer, as well as on its thickness, have been determined and discussed. It is shown that practically the total collection of charges generated by AM1.5 solar radiation, the uncompensated acceptor concentration, electron lifetime and thickness of the CdTe absorber layer should be equal to 1015–1016 cm−3, 10−9–10−8 s and several tens of micrometres, respectively