Dielectric properties of CdxZn1-xTe epilayers

We report on the dielectric properties of CdxZn1-xTe (0.056less than or equal toxless than or equal to0.582) epilayers studied by capacitance and dissipation factor measurements at temperature 201 K<T<460 K and frequency 20 Hz<f<1 MHz. A Debye-like relaxation in the dielectric response has been observed, which is explained in terms of the presence of charge redistribution. The relaxation is found to be a thermally activated process, and the activation energies obtained from both dissipation factor and capacitance are in good agreement. It is also found that the activation energy decreases with increasing Cd content and this behavior is interpreted in terms of the four-center model, in which the number of Cd atoms appearing in the nearest-neighbor sites of a defect can have four possible configurations. In addition, we demonstrate that the transport mechanism of the carrier conduction in CdZnTe epilayers can be well described by the correlated barrier hopping model. (C) 2003 American Institute of Physics.