Electron Affinity Difference in CdS/Si Solar Cells

Abstract

The electron affinity difference ΔEc=χ1-χ2, in CdS/Si solar cells fabricated by four different processes is measured from observations of the variations of open circuit voltage with temperature. For CdS/Si cells, the values of ΔEc lie between 0.43 and 0.48 eV and are found to be independent of the process of cell fabrication. The use of CdZnS in place of CdS decreases the value of ΔEc to 0.3 eV. The method used for the measurement of ΔEc is very simple. The values of the saturation current I0 for different types of cells are estimated from the slopes of qVoc versus kT characteristics and compared with those obtained from ln I versus V curves. The values of I0 found for each cell by the two methods are in good agreement.