Abstract
We report on room temperature electrically-induced terahertz emission from interdigitated GaN quantum well structures. The emission spectrum has been analysed in a Michelson interferometer using a 4K-Si bolometer as a terahertz detector. A resonant peak at the frequency of around 3 THz was observed in emission spectra. A threshold behaviour of the resonance with respect to applied voltage takes place. By using the proposed analytical model the measured/observed experimentally resonant behaviour of emission spectra is interpreted as a result of ungated stream-plasma instability in the channel.