Impedance spectroscopy of p-ZnGa2Te4/n-Si nano-HJD

The dielectric relaxation and alternating current mechanisms of nano-crystalline p-ZnGa2Te4/n-Si heterojunction diode (HJD) were investigated by complex impedance spectroscopy over a wide range of temperature (297-473 K) and a frequency range (42 Hz-5 MHz). The bulk resistance Rb as well as the bulk capacitance Cb were found to increase with increasing temperature. The dc conductivity exhibits a typical Arrhenius behavior. The electrical activation energy ΔEσ was determined to be (0.28 eV). The ac conductivity spectrum was found to obey Jonscher's universal power law. The frequency exponent s decreases slightly with increasing temperature. The temperature dependence of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping (CBH) model. The dielectric constant ε1(ω) and dielectric loss ε2(ω) were found to decrease with increasing frequency and to increase with increasing temperature. The mean value of the exponent m decreases with increasing temperature. The dielectric analysis is described by non-Debye type behavior.