Growth and characterization of ZnIn2Se4 buffer layer on CuInSe2 thin films

The p-type CuInSe2 (CIS) films were prepared by electrodeposition following the vacuum annealing process. Zn element was diffused into the CIS film samples at 350 °C by heating Zn grains in vacuum. Then, ZnIn2Se4 (ZIS) buffer layer was fabricated on CIS thin film by this thermal diffusion process. The formation of ZIS phase was confirmed by X-ray diffraction pattern (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Dark I–V measurement shows that the Zn-doped CIS (0.89 at%)/Mo structure reveals the rectifying property, which indicates that a p–n junction was formed.