CdS/CdTe Analysis and Modeling

Abstract

Simple mathematical solar models are introduced, starting from diode models with various amounts of adjustable parameters. Model applications are discussed. Current voltage characteristics are analyzed. Extensive comparison is made with different cell types and different production modes. Encouraging results are obtained from specific diode models with only two adjustable parameters showing surprising agreements with a large number of experiments. These results are compared with the solution curves (current voltage characteristics) of the transport and Poisson equations that contain in addition to some well-known parameters as e.g. band gap, optical absorption constant, and carrier mobility and some derived parameters, as minority carrier life time, most parameters that determine the quasi Fermi levels and band interconnections are missing. Consequently, even though the integration of this set of equations delivers instructive distribution of carrier density, space charges, potential and field distributions, the large quantity of adjustable parameters renders the results questionable and possibly misleading.