Effect of Annealing Temperature and Thickness on the Structural and Optical Properties of CdSeThin Films


CdSe alloy has been prepared successfully from its high purity elements. Thin films of thisalloy with different thicknesses (300,700)nm have been grown on glass substrates at roomtemperature under very low pressure (10-5)Torr with rate of deposition (1.7)nm/sec bythermal evaporation technique, after that these thin films have been heat treated under lowpressure (10-2)Torr at (473,673)K for one hour. X-ray patterns showed that both CdSe alloyand thin films are polycrystalline and have the hexagonal structure with preferentialorientation in the [100] and [002] direction respectively. The optical measurements indicatedthat CdSe thin films have allowed direct optical energy band gap, and it increases from (1.77-1.84) eV and from (1.6-1.65)eV with the increase in temperature from (R.T-673)K forthicknesses. (300,700)nm, respectively. The optical constants (refractive index, extinctioncoefficient and the real, imaginary parts of dielectric constant) were also studie