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Effect of annealing and composition on crystal structure, surface morphology and optical absorption of chemically deposited Cd 1‐x Sn x S films
Author(s) -
Das R.,
Kumar R.
Publication year - 2010
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201000030
Subject(s) - annealing (glass) , crystallinity , crystallite , materials science , lattice constant , thin film , grain size , doping , analytical chemistry (journal) , scanning electron microscope , absorption spectroscopy , crystallography , diffraction , chemistry , nanotechnology , optics , composite material , physics , optoelectronics , chromatography
Cd 1‐x Sn x S thin films were successfully deposited on suitably cleaned glass substrate by chemical bath deposition method at 74 °C. Hydrated Stannous Chloride (SnCl 2 .2H 2 O) in aqueous solution was added to the CdS growing solution in different proportions. The experimental results indicate, a successful doping for lower concentration of Sn, saturation for intermediate doping levels, and a degradation of the doping process for higher concentration of Sn. Indirect (X‐ray diffraction) and Direct (Scanning electron microscopy) measurements were performed to characterize the growth and the nature of crystallinity of the different Cd 1‐x Sn x S films. The effect of annealing on the crystal structure and morphology of the deposited films has also been discussed. The X‐ray diffraction spectra show that the thin films are polycrystalline and have both cubic and hexagonal structure. The Interplanar spacing, lattice constant, grain size, strain, and dislocation density were calculated for as‐deposited and annealed films. The grain size was found to decrease from 5 nm to 0.89 nm with doping concentration of Sn. The grain size further decreased due to annealing at 400 °C. SEM studies show layered growth and long needle like structures along with some voids. After annealing the densification and smaller size of the particles was also observed. The optical absorption spectra show shifting of absorption peaks towards lower wavelength side (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)