Comprehensive physical studies on nanostructured Zn-doped CdSe thin films

Abstract

Electrochemically deposited un- and Zn-doped CdSe nanostructures have been examined in this study. An aqueous solution having 3CdSO4·8H2O, SeO2, and various amounts of ZnSO4·7H2O was used to deposition un- and Zn-doped CdSe samples. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray analysis (EDXA) attachment, atomic force microscopy (AFM), room temperature photoluminescence (PL), and UV–Vis spectroscopy have been served to study the impact of Zn-dopant on the physical characteristics of CdSe thin films. All samples had a cubic crystalline system and their crystallite size was 7–9 nm. The lattice constant (a), unit cell volume (V), and the interplanar distance of CdSe samples were reduced after Zn-doping. FESEM images presented grain-like morphology for all samples. According to AFM results, the surface smoothness of Zn-doped CdSe samples was improved compared to the undoped CdSe sample. Two observed PL emission peaks at 564 and 690 nm were associated with the recombination of electron-hole and the near band emission (NBE) of CdSe, respectively. The intensity of PL spectra of CdSe samples was decreased after Zn-doping, which related to the generation of non-radiative relaxation of electron transition. According to UV–Vis spectroscopy results, the Eg of undoped CdSe sample was 1.73 eV that it reduced to 1.67 eV for Zn-doped CdSe samples. The optical- and electrical conductivity of CdSe thin films have been improved due to Zn-doping. Accordingly, the obtained results confirmed that the Zn dopant plays a key role in the physical properties of nanostructured CdSe thin films.