Structural and electrical properties of evaporated ZnTe thin films

Zinc telluride thin films of various thicknesses are deposited by vacuum evaporation onto glass substrates at room temperature. The X-ray diffraction technique is used to determine the crystalline structure and grain size of the films, respectively. The structure was found to be cubic with preferential orientation along a (1 1 1) plane and crystallite size of about 50-80 nm. The degree of preferred orientation and crystallite size are increased as the film thickness increases. The current density-voltage (J-V) characteristics showed ohmic conduction in the lower voltage range and space-charge-limited conductivity in the higher voltage range. Capacitance measurements indicated that the films have a relative permittivity, ε_r, of approximately 8.19. Further evidence for this conduction process was provided by linear dependence of V_t on d². Analysis of the results yielded hole concentration , which is correlated with the structural properties.