Band structure and Optical properties CdTe and CdSn[sub 3]Te[sub 4] thin films

Abstract

CdTe and CdSn3Te4 compounds were prepared by direct reaction of their high purity elemental constituents using rotating furnace. Optimal deposition conditions for the deposition of CdTe and CdSn3Te4 thin films in hot wall evaporation setup were simulated using Monte Carlo technique. Thin films of CdTe and CdSn3Te4 were deposited on glass substrates by hot wall evaporation method. From the XRD measurements it was found that the films of CdTe and CdSn3Te4 were of cubic zinc‐blende and rock salt structures respectively. The lattice parameters were determined as a = 6.476 Å (CdTe) and a = 6.238 Å (CdSn3Te4) from the XRD data. The UV‐Vis‐NIR optical transmittance spectra of thin films of different films were obtained and it was found that the direct optical band gaps were 1.4 eV (CdTe) and 0.8 eV (CdSn3Te4). Electronic structure, band parameters and optical spectra of CdTe and CdSn3Te4 were calculated from ab initio studies within the GGA approximation. The experimental results were in good agreement with the theoretical values.