Influence of Ni-Co dual doping on structural and optical properties of CdSe thin films prepared by chemical bath deposition method

Abstract

Pure and Ni-Co dual doped CdSe thin films were deposited on glass substrate by chemical bath deposition (CBD) technique. The deposited thin films were annealed for 1 h at 500 °C. X-ray diffraction (XRD) and UV–vis Spectroscopy were used to study the structural and optical properties of the prepared thin films. XRD studies revealed the hexagonal phase for pure CdSe, CdSe: 0%Ni-8%Co, CdSe: 2%Ni-6%Co, CdSe: 6%Ni-2%Co and CdSe: 8%Ni-0%Co thin films, while CdSe: 4%Ni-4%Co produced the cubic phase. The XRD results revealed that the dual doping affected strongly the preferred orientation of the crystallites. The optical band gap energy, Urbach energy, Extinction coefficient, refractive index, real and imaginary dielectric constants and optical conductivity were calculated for all obtained thin films. The direct optical band gap energy of pure CdSe film was 1.43 eV and it decreased with Ni and Co dual doping. The lowest optical band gap energy was observed for CdSe: 4%Ni-4%Co. The dual doping with Ni and Co increased the efficiency of CdSe thin films to be used as solar cells.