Thin Solid Films, Vol.269, No.1-2, 112-116, 1995
Structural Dependence of DC Electrical-Properties of Physically Deposited CdTe Thin-Films
The structural and electrical properties of physical vapour deposition thin films of cadmium telluride of thickness up to 800 nm were investigated. X-ray diffraction studies showed that the films were polycrystalline with a crystallite size of 82-129 nm and a preferred orientation of the [111] fibre texture. The degree of preferred orientation increased as the film thickness increases. Capacitance measurements indicated that the films have a relative permittivity, epsilon(p) of approximately 8.91. The current density-voltage characteristics showed ohmic conduction in the lower voltage range and space-charge-limited conductivity in the higher voltage range. Further evidence for this conduction process was provided by the linear dependence of V-t on t(2) and of log J on log t. Analysis of the results yielded an electron concentration n(0) = (1.29-6.28) x 10(10) m(-3), which is correlated with the crystallite size. The ratios of the free charge to the trapped charge, Theta = (1.49-8.59) x 10(-11) were estimated and the traps concentration, N-T, has been correlated with the degree of preferred orientation.