Effect of Cu/In ratio on properties of CuInSe2thin films prepared by selenization of Cu-In layers

In this paper, the chalcopyrite CuInSe2 thin films were fabricated from a selenization of electrodeposited Cu-In layers. In this study, the electrodeposition time of the In layer was set, but that for the Cu layer was not. The thin films were selenized in a sealed glass tube with pure Se powder by three different Cu layer samples at various electrodeposition times at 500 °C for 2 hours. An FE-SEM image of the sample shows that the copper-rich product has irregular agglomerates with a dense surface. The X-ray diffraction patterns show CuInSe2 peaks for all samples. However, the X-ray diffraction pattern reveals CuSe2 peaks when the electrodeposition time of the Cu layer increases. On the other hand, the band gap (Eg) of the samples decreases from 1.15 to 1.07 eV when the Cu/In ratio increases.