OPTTR induced current oscillations in GaN diodes Monte Carlo simulations
At very low temperature, when optical phonon emission is the dominant scattering mechanism, the phenomenon known as Optical Phonon Transit Time Resonance (OPTTR) may originate current oscillations in n+ nn+ diodes at frequencies in the terahertz range. In this work, by means of Monte Carlo simulations, we study the optimum conditions for the onset of such mechanism in GaN diodes. For this purpose, we analyze the influence of the following quantities: applied bias, temperature, length and doping of the n region. Under certain conditions, simulations show clear current oscillations which are enhanced when providing a characteristic frequency close to the plasma frequency of the active region. Even so, it is possible to achieve some degree of tunability of that oscillation frequency by varying the applied voltage and the length of the n region.