Monte Carlo simulation of THz maser based on optical phonon transit time resonance in GaN

The linear and nonlinear analysis of microwave power amplification and gene ration in the terahertz (THz) frequency range is carried out by the Monte C arlo method in bulk wurtzite GaN. It is shown that a dynamic negative diffe rential mobility (DNDM) persists up to 80 K due to the transit-time resonan ce associated with optical phonons. The generation frequency depends almost linearly on the static electric held strength and can be tuned in the wide frequency range from 0.2 to 3 THz when the electric field varies from 1 up to 12 kV/cm. The optimum amplitude of the microwave electric field generat ed by bulk GaN is found to be of the order of the static electric field thu s leading to a significant maximum efficiency of about 1 to 1.5% for microw ave power generation in the THz frequency range.