Evidence for CdTe1#x2212;xSx compound formation in CdTe solar cells from high-precision, temperature-dependent device measurements

摘要

High-precision, temperature-dependent device measurements have been made on CdTe solar cells fabricated by close-spaced sublimation on CdS-coated SnO2:F-glass substrates. In particular, the temperature dependence of Voc was measured from 110 K–310 K, taking care that the wavelengths of the incident light did not overlap the absorber band edge. The conventional deduction of the absorber bandgap Eg was clarified by taking into account its temperature dependence. Depending upon fabrication conditions, it was found that the 0 K extrapolated bandgap of the region of the absorber in which most recombination occurs was 1.33 e V, i.e. significantly less than that of CdTe. It was concluded that this region consists of the compound CdTe1−xSx.