Comparative study of structural, optical and electrical properties of electrochemically deposited Eu, Sm and Gd doped ZnSe thin films

• Published in: Journal of materials science. Materials in electronics 2018-04, Vol.29 (7), p.5638-5648
• Main Authors: Kumar, T. Rajesh, Prabukanthan, P., Harichandran, G., Theerthagiri, J., Moydeen, A. Meera, Durai, G., Kuppusami, P., Tatarchuk, Tetiana
• Format: Article
• Language: English
• Subjects: Cations; Characterization and Evaluation of Materials; Charge transfer; Chemistry and Materials Science; Current carriers; Electrical properties; Electron microscopy; Gadolinium; Impedance measurement; Materials Science; Optical and Electronic Materials; Optical properties; Photoluminescence; Rare earth elements; Samarium; Substrates; Thin films; Wurtzite; X ray analysis; Zinc coatings; Zinc selenide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-8533-2

A facile approach involving electrochemical deposition method was utilized to coat ITO substrate with zinc selenide thin films at different rare earth metal (Eu 3+ , Sm 3+ and Gd 3+ ) ions. The characteristics of deposited films were studied in relation with the doped metal ions. The structure of the coating was confirmed to be hexagonal wurtzite in (101) plane by X-ray analysis. The new antistructural modeling shows that the doping of ZnSe lattice by rare earth cations increases the concentration of the surface active centers such as Gd Zn · , Eu Zn · , Sm Zn · , and V Zn ″ , which are located in the cationic sublattice. XRD data revealed that the average crystallite size of ZnSe and ZnSe:Eu, ZnSe:Sm, and ZnSe:Gd was 63, 54, 47, and 49 nm, respectively. The morphological results by scanning electron microscopy indicate that the spherical-like structure with agglomeration of grains and a slight increase in the particle size. Energy dispersive X-ray, UV–Visible and photoluminescence spectroscopy were used to study the composition and optical properties of the films. A blue-shift was observed in ZnSe thin films. The bandgap energy of undoped ZnSe and ZnSe:Eu, ZnSe:Sm, and ZnSe:Gd were found to be 2.28, 2.44, 2.68 and 2.75 eV, respectively. Among the different coated films, the Gd 3+ ion doped ZnSe thin film exhibited a lesser charge transfer resistance of 25.5 Ω as analyzed from the electrochemical impedance measurement. The photoelectrochemical studies reveal that the rate of photoinduced charge carriers was higher in Gd 3+ ion doped thin film. The present studies suggested that the Gd 3+ ion doped ZnSe thin film can be a promising material for electrochemical device applications.