Effect of absorber layer parameters on charge collection in thin-film CdS/CdTe solar cells

The dependence of charge collection efficiency of CdS/CdTe solar cells on the uncompensated acceptor concentration Na - Nd, 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 total charge collection can be achieved practically If the electron lifetime is equal to several microseconds and the CdTe layer thickness is greater than that typically used in the fabrication of CdTe/CdS solar cells. If the electron lifetime in the CdTe layer is in the range of 10⁻⁹–10⁻¹⁰ s, short-circuit current density of 25–26 mA/cm² (generated by AM1.5 solar radiation) can be attained when Na - Nd is close to 10¹⁶ cm⁻³.