Low- and High-Frequency C-V Characteristics of Au/n-GaN/n-GaAs

Au/GaN/GaAs Schottky diode created by the nitridation of n-GaAs substrate which was exposed to a flow of active nitrogen created by a discharge source with high voltage in ultra-high vacuum with two different thicknesses of GaN layers (0.7 nm and 2.2 nm), the I-V and capacitance-voltage (C-V) characteristics of the Au/n-GaN/n-GaAs structures were studied for low- and high-frequency at room temperature. The measurements of I-V of the Au/n-GaN/n-GaAs Schottky diode were found to be strongly dependent on bias voltage and nitridation process. The electrical parameters are bound by the thickness of the GaN layer. The capacitance curves depict a behavior indicating the presence of interface state density, especially in the low frequency. The interface states density was calculated using the high- and low-frequency capacitance curves and it has been shown that the interface states density decreases with increasing of nitridation of the GaAs.