Effect of annealing and composition on crystal structure, surface morphology and optical absorption of chemically deposited Cd_1‐xSn_xS films

Abstract

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.

Modification of the Structural Characteristics of the Tungsten Powder through Short Mechanical Milling Processes

“…where: λ is the wave length of the Cu Kα radiation; B is the full-width-at-half-maximum FWHM for the samples; B 0 is FWHM for the etalon (the WO sample); θ -the diffraction angle.The internal stress, is given by the relation [4]:…”

“…We have considered that the dislocations at the limit of the crystallite show a random distribution. The dislocation density after Williamson-Smallman was calculated using the formula [4,6]:…”