Investigation of electrical properties of In/ZnIn2Te4/n-Si/Ag diode

In/ZnIn2Te4/n-Si/Ag diode structure was fabricated by the thermal deposition of a ZnIn2Te4 thin film on n-Si wafer substrate with Ag metal back contact. The structural characteristics of the film were investigated in terms of composition, X-ray diffraction and topographic measurements. The diode structure was completed by evaporating In metal on the film surface as a top contact. The diode parameters as saturation current, barrier height, ideality factor and series resistance values were determined from the semi-logarithmic forward bias current-voltage characteristics of the diode. According to the assumption of the thermionic emission model, the ideality factor was found higher than unity and it was also observed that the barrier height and ideality factor showed a temperature-dependent profile resulting from the non-ideality in the current-voltage behaviour of the diode. As a result, the model was modified by considering inhomogeneous barrier formation and Gaussian distribution was expected to be dominant on 1.37 eV mean barrier height with a deviation of 0.18. In addition, the voltage dependence of these Gaussian diode parameters was investigated. The forward and reverse bias capacitance and conductance measurements showed that there was a slight change in capacitance values with frequency whereas the conductance values decreased with increase in frequency. In addition to the current-voltage analysis, the distribution of density of interface states and the values of series resistance were evaluated as a function of bias voltage and frequency.