Effect of Cu/In ratio on properties of CuInSe_2 thin films prepared by selenization of Cu-In layers

摘要

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 ℃ 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 CuInSe_2 peaks for all samples. However, the X-ray diffraction pattern reveals CuSe_2 peaks when the electrodeposition time of the Cu layer increases. On the other hand, the band gap (E_g) of the samples decreases from 1.15 to 1.07 eV when the Cu/In ratio increases.