Publication: Structural and optical characterization of As-grown and annealed ZnxCd1-xS thin-films by CBD for solar cell applications
Date
2020
Authors
Ahamed E.M.K.I.
Das N.K.
Gupta A.K.S.
Khan M.N.I.
Matin M.A.
Amin N.
Journal Title
Journal ISSN
Volume Title
Publisher
International Journal of Renewable Energy Research
Abstract
We report the synthesis of ZnxCd1-xS (x=0 to 0.41) thin-films by chemical bath deposition technique and annealing of the as-grown Zn0.31Cd0.69S films at 200�C, 350�C and 500�C. The structural properties, optical properties, surface morphology and elemental composition of the films are characterized by XRD, UV-Vis N.I.R. spectroscopy, EDX. and FESEM. The thickness of the as-grown films is measured by the DEKTAK stylus profilometer and is in the range of ~100 nm-120 nm. The as-grown films show quasi-crystalline nature with preferential orientation along (002) hexagonal plane and the crystallinity is declined with the increment of zinc content. Also, the FESEM micrographs show the homogeneous growth, pinhole-free surface and compactness of the films. The transmission edge is shifted towards the short wavelength region as the relative zinc content increases, which confirms the significant reduction of photon absorption in the blue region of the solar spectrum. The as-grown films show average transmittance of ~80-90% along with a tunable bandgap of 2.50eV to 3.35eV for the variation of relative zinc content from 0 to 0.41. The annealing treatment improves the crystalline properties of Zn0.31Cd0.69S film and the best crystallinity is obtained at 350�C temperature. Meanwhile, the annealed Zn0.31Cd0.69S films also exhibit a variable bandgap of 2.85eV, 3.10eV and 3.22eV at 200�C, 350�C and 500�C respectively whereas the bandgap of the as-grown film is 3.12eV. Annealed Zn0.31Cd0.69S thin-film at 350�C having enhanced structural properties without affecting optical characteristics and therefore it can be suitable as a good alternative buffer layer for thin-film solar cell applications. � 2020 International Journal of Renewable Energy Research.
Description
Absorption spectroscopy; Annealing; Binary alloys; Buffer layers; Crystallinity; Deposition; Energy gap; Morphology; Optical films; Optical properties; Semiconductor alloys; Structural properties; Surface morphology; Thin film solar cells; X ray diffraction; Zinc; Annealing; As-grown; As-grown films; Chemical-bath deposition; FESEM; Thin-films; UV-vis-NIR; XRD; Zinc content; Znxcd1-xS; Thin films