The electron affinity difference in CdS/CdTe solar cells

The electron affinity difference ΔEc=χ1−χ2, 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 ΔEc 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 ΔEc to 0·49 eV. The method used for the measurement of ΔEc is very simple. The values of the saturation currentI0 for the different types of cells have been estimated from the slopes ofqVoc versuskT plots and compared with those obtained fromlnI versusV curves. The values ofI0 found for each cell by the two methods are in substantial agreement.