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 Δ^Eσ 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.