An analyzing of anomalous peak in the capacitance-voltage characteristics at Hg/GaN Schottky contact

The frequency dependence of capacitance-voltage (C-V) characteristics of Hg/GaN and Hg/InGaN/GaN Schottky contacts are investigated for 1KHz, 10KHz and 1MHz at room temperature. An anomalous peak in the C-V curves of Hg/GaN sample is observed but no peak for the Hg/InGaN/GaN sample occurs. The interface states, series resistance and minority-carrier injection would be the origin of this anomalous peak. The interface states density is calculated through C-V measurement of high and low frequencies, and a four-element circuit model is proposed to determine the series resistance. In addition, energy bind structures are taken into account. The three aspects above are analyzed for both two samples, and the origin of the anomalous peak is attributed to the series resistance and minority-carrier injection rather than the interface states.