Optical and structural characterization of CdSe and CdTe layers and fabrication of a CdTe/CdSe structure

CdTe/CdSe heterojunction solar cell structure is fabricated using a simple, easy and low-cost electrodeposition method. To fabricate this solar cell structure, CdSe and CdTe thin films are deposited onto FTO-coated glass substrates by low-cost electrodeposition method. The optimized growth conditions are first chosen for both CdSe and CdTe layers by investigating the photoelectrochemical, optical, structural and morphological properties of the deposited films. PEC measurements showed n-type conductivity of CdSe films and p-type conductivity of CdTe films, respectively. Optical absorption measurements showed that the band gap of CdSe layers lies in the range 1.75-2.14 eV and the band gap of CdTe layers lies in the range 1.44-1.50 eV. XRD study reveals that CdSe and CdTe films are polycrystalline with preferential orientation of (1 1 1) plane with cubic phase. SEM study reveals that both layers are smooth, void free and uniformly distributed over the surface of the substrates. After getting the good quality of CdSe and CdTe layers, a fabrication of CdTe/CdSe heterojunction solar cell have been performed. I-V characteristics of metal/CdTe/CdSe/FTO/glass structure have been investigated under dark condition and showed rectification behavior.