Microstructural evolution of oxygen incorporated CdTe thin films deposited by close-spaced sublimation

In this work, cadmium telluride (CdTe) thin film was deposited in vacuum (pure argon ambient) as well as different argon (Ar) and oxygen (O2) ambient conditions using close-spaced sublimation (CSS) method at the deposition pressure of 1 Torr. The deposited films were characterized via X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV-Vis spectrophotometer and Hall Effect measurement for the analysis of structural properties, morphology, optical properties and electrical properties, respectively. XRD patterns exhibited almost similar preferential orientation plane at (1 1 1) irrespective of the O2 concentration. SEM surface morphology microstructure revealed that O2 presence had a substantial effect on grain size reaching up to 7.19 mu m. Optical properties also demonstrated insignificant changes in the direct band gap values of around 1.48 eV. Carrier concentration showed an upward trend in the order of 1013 cm-3, whereby resistivity and mobility did not change substantially either in vacuum (pure Ar ambient) or in Ar/O2 ambient.