Effect of in-situ CdCl2 treatment on spray deposited CdTe films:: Photoluminescence study

In-situ CdCl2 treatment for spray deposited CdTe films has been done by spraying a 0.01 M CdCl2 solution on US substrates. Scanning electron micrographs show the improvement in grain growth with the CdCl2 spray. Photoluminescence spectra for films with the in-situ treatment show a shift in the bandgap by 0.06 eV and a reduction in the defect band intensity as compared to those for the films without the treatment. The shift is due to conversion of CdTe into CdTeS by S diffusion from the CdS substrate. Our studies show that an in-situ CdCl2 treatment is effective in improving the CdTe thin film properties.