Electrical characterization of Au/Pd/n-GaN/Pd/Au device structure in the radio frequency range by simulation study

GaN based devices are highly promising optoelectronic devices for many years due to their useful applications in photovoltaic energy conversation, fiber optic communication and atmosphere monitoring. GaN based devices such as Schottky barrier, metal-semiconductor-metal and p-i-n structure have been fabricated and characterized so far. A proper understanding of the impedance or admittance spectroscopy result is crucial since it is a powerful tool to calculate the physical and electronic parameters of a device. In this study, temperature dependent dark current-voltage (I-V) and dark impedance spectra of n type GaN based metal-semiconductor-metal device have been studied with current-voltage and impedance spectra by simulation. All current-voltage characteristics exhibited good rectification behavior. The forward and reverse bias capacitance-voltage (C-V) characteristics of the Au/Pd/n-GaN/Pd/Au device were simulated at 2 MHz probing frequency. Nyquist plots of simulated device at 295 K are shown that two-barrier heights can be observable above critical threshold bias point. Frequency depended inverse dielectric loss tangent spectra of Au/Pd/n-GaN/Pd/Au device at different DC bias voltages also shows significant two peaks. This indicates that our simulation is extremely useful for determination of potential barrier numbers. (C) 2011 Elsevier B.V. All rights reserved.