STRUCTURAL AND OPTICAL-PROPERTIES OF CDXZN(1-X)TE THIN-FILMS

Seven CdxZn(1-x) Te solid solutions with x = 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 were synthesized by fusing stoichiometric amounts of CdTe and ZnTe constituents in silica tubes. Each composition was used in the preparation of a group of thin films of different thicknesses. Structural investigation of the obtained films indicates they have a p olycrystalline structure with predominant diffraction lines correspond ing to (111) (220) and (311) reflecting planes, which can be attribute d to the characteristics of growth with the (111) plane.The optical co nstants (the refractive index n, the absorption index k, and the absor ption coefficient alpha) of CdxZn(1-x) Te thin films were determined i n the spectral range 500-2000 nm. At certain wavelengths it was found that the refractive index, n, increases with increasing molar fraction , x. It was also found that plots of alpha(2) (hv) and alpha(1/2) (hv) yield straight lines, corresponding to direct and indirect allowed tr ansitions respectively obeying the following two equations: E(g)(d) = 1.583 + 0.277x + 0.197x(2) E(g)(ind) = 1.281 + 0.111x + 0.302x(2).