Analysis of interface states in Au/ZnO/p-InP (MOS) structure

Zinc oxide (ZnO) film was deposited on p-type InP substrate by means of radio frequency magnetron sputtering technique and thus the Au/ZnO/p-InP (MOS) structure was fabricated. The crystal structure and surface morphology of ZnO film deposited on InP were characterized by X-ray diffraction and atomic force microscopy, respectively. The analysis of interface states of the structure is studied using admittance (Y = G + i omega C) measurements at room temperature. It is observed that the capacitance and conductance measurements change with frequency. This change is attributed to the presence of interface states. To determine the interface state density (N-ss), the high-low frequency (C-HF-C-LF) capacitance, Hill-Coleman and conductance methods were used. The N-ss values obtained from these methods are in agreement with each other. Furthermore, the effect of the series resistance (R-s) on admittance measurements was investigated. Thus, the obtained results suggest that the prepared structure can be used in various electronic applications.