Oscillations in GaN Diode with 2D-h-BN – Layer

In this research, we have investigated the operation of a hybrid 2D-3D heterostructure diode in the Gunn-like oscillation mode. The diode is represented as a GaN-based structure containing n-type channel on a sapphire substrate with the hexagonal boron nitride (h-BN) monolayer on the top. The simulation of the diode operation has been carried out by using the ensemble Monte Carlo technique self-consistently with a numerical solution of system heat equations. The model of heating based on macroscopic thermal parameters of materials has been used. Diode length is assumed to be about 1 μm and the donor concentration is 0.6·1023 – 1023 m – 3. Direct current and oscillation characteristic of diodes with and without the h-BN monolayer have been compared. Maximal oscillating efficiency has been estimated in the possible bias range taking into account impact ionization and heating effect condition.Our simulation shows that microwave oscillation in the n+-n-n+ GaN diode is limited by impact ionization and self- heating and depend upon the bias and doping concentration. Temperature distributions in the diode have been obtained. With the higher concentration the oscillation can be fully suppressed by both impact ionization and heating. There is a narrow bias range where the oscillation appears. Adding the h-BN monolayer on the top of the diode surface can decrease a local overheating effect. It has been demonstrated that presence of h-BN affects the temperature magnitude and redistribution in the transit region of the diode. The frequency range for this case is narrower and the maxi-mal efficiency is five times lower in comparison with case when the diode was not affected by impact ionization and temperature. In several cases of high doping, the microwave oscillations appear only in the diode with the h-BN monolayer.