The electron affinity difference in CdS/CdTe solar cells

Abstract

The electron affinity difference AEc = Xl -;t2, in CdS/CdTe solar cells fabricated by four different processes has been measured from observations of the variations of open voltages with temperature. For CdS/CdTe cells, the values of AEc lie between 0.20 and 0.25 eV and are found to be independent of the process of cell fabrication. The use of CdZnTe in place of CdTe increases the value of AEc to 0.49 eV. The method used for the measurement of AE~ is very simple. The values of the saturation current Io for the different types of cells have been estimated from the slopes of qVo~ versus kT plots and compared with those obtained from lnI versus V curves. The values of I0 found for each cell by the two methods are in substantial agreement.