Influence of CdCl2 Treatment Temperature on Structural and Optical Properties of CdTe Thin Films

In this work the influence of the CdCl2 treatment temperature on the structural, morphological, and optical properties of CdTe thin films were investigated. The CdTe films were grown on CdS coated borosilicate glass by Close- Spaced Sublimation (CSS) technique using a standard recipe. The CdS coating was done by RF sputtering. The deposited CdTe films were treated with aqueous CdCl2 solution of 0.3 M molar concentration at 380°C, 385°C, 390°C, 395°C and 400°C for 25 minutes each. All the treated films show polycrystalline nature with intense peak at (111) orientation. The highest prominent peak and the largest crystallite size were found for 395°C treatment temperature. The SEM study confirms that the film treated at 395°C temperature is compact and shows uniform surface morphology. Sharp transmittance edges are found at 830 nm wavelength for all treated films which also signifies the higher crystallinity, suitable for high performance CdTe solar cell application.