Characterization of hot wall deposited CdSe0.6Te0.4 thin films

摘要

CdSexTe1-x thin films are of great practical interest owing to their unique properties, which make them suitable for solar cell applications. By varying the Se and Te contents, the hand gap can be suitably tailored to fit for selected applications. In our present work we have deposited CdSe0.6Te0.4 thin films onto glass substrates by hot wall deposition technique using the synthesized CdSe0.6Te0.4 compound. CdSe0.6Te0.4 compound has been synthesized by direct reaction of elemental cadmium, selenium and tellurium taken in suitable weight proportion. The hot wall setup consists of quartz tube over which kanthal wire is wound with equal spacing to get uniform heat distribution through out the tube. The X-ray diffraction studies were carried out on all the deposited CdSe0.6Te0.4 films and it revealed that the films are polycrystalline in nature exhibiting both hexagonal and cubic phases. The composition of the films has been studied using energy dispersive X-ray analysis (Cd = 49.10 at%, Se = 29.05 at % and Te = 21.85 at %). The optical properties of the films have been studied using the UV-Vis-NIR spectrophotometer and from the transmittance spectra the optical parameters like band gap, refractive index and absorption coefficient has been evaluated. The CdSe0.6Te0.4 films were found to have direct band gap. The band gap and refractive index have been found to be 1.48 eV and 2.2 respectively.