Electroreflectance spectrum of CdTe1-xSx mixed crystal layer in CdS/CdTe thin-film solar cell

The electroreflectance (ER) spectrum of the CdS/CdTe thin-him solar cell has been studied in conjunction with the results on the atomic element depth profile. The ER spectrum occurs with three spectral components with optical transition energies of 1.44 eV, 1.47 eV and 1.49 eV at 293 K. The mixed crystal layer of CdTe1-xSx, similar to 2 mu m thick (x > 0.004), extends from the CdS/CdTe metallurgical interface into the CdTe layer, and the n-p junction locates in the mixed crystal layer. The dominant 1.47-eV ER component is assigned to the band gap of the mixed crystal layer of CdTe0.95S0.05 at around the n-p junction.