Structural and optical properties of hot wall deposited CdSe0.15Te0.85 thin films

Abstract

CdSe0.15Te0.85 thin films have been deposited on glass substrates by hot wall deposition technique, using bulk CdSe0.15Te0.85 material prepared by direct reaction of high-purity elemental cadmium, selenium and tellurium. X-ray diffraction studies revealed that the films are polycrystalline in nature, single-phase exhibiting cubic zinc blende structure with strong preferential orientation of grains along the (111) direction. Strain, grain size and dislocation density have been estimated. The grain size is found to increase with increasing film thickness. The composition of the film has been determined by energy dispersive X-ray analysis. Surface morphology of the film has been studied using a scanning electron microscope. The transmittance characteristics of the CdSe0.15Te0.85 thin films have been used to determine the nature of the transition, and the transition is found to be direct allowed. The energy band gap has been determined. The refractive index of the CdSe0.15Te0.85 thin films have also been evaluated from the transmittance spectra.