Characterization of CdTe thin film—dependence of structural and optical properties on temperature and thickness

The X-ray diffraction analysis of vacuum-evaporated cadmium telluride (CdTe) films reveals that the structure of the films is polycrystalline in nature for the samples prepared at higher substrate temperatures. The crystallite size (D), dislocation density (δ) and strain (ε) were calculated. The composition analysis was made by the energy dispersive X-ray analysis. It confirmed the equal distribution of Cd and Te elements in the CdTe films. The fundamental optical parameters like band gap and extinction coefficient are calculated from the transmission spectra. The possible optical transition in these films is found to be direct and allowed. The charge transport phenomenon appears to be space charge limited conduction. Various electrical parameters were determined from the I–V analysis.