GaN and related materials have recently attracted a lot of interest for applications in high-power electronics capable of operation at elevated temperatures and radiation environment. Group III-Nitrides and their ternary and multinary systems offer numerous advantages. These include wider bandgaps as well as excellent transport and thermal characteristics. The remarkable properties of Group III-Nitrides have led to rapid progress in the realization of a broad range of electronic devices. Despite the rapid progress in the upper frequency limits and RF power levels of three-terminal devices the representatives of two-terminal devices, in particular, resonant-tunnelling diodes (RTDs) still play an important role in many system applications at frequencies above about 50 GHz. If RTDs could be produced in the Group III-Nitride system, a number of novel possibilities exist for development and exploitation. If RTDs can be made in Group III-nitrides, a whole new high-power microwave technology could be realised.
Thus, the goal of this communication is two-fold. First, we address experimental and theoretical study of a two-dimensional electron gas (2DEG) transport at low and moderate electric fields. In particular, we concentrate on hot-electron effects and self-heating phenomena. Separation between these effects is important to clarify the thermal budget of devices. The second point concerns with growth conditions influence on performance of nitride-based quantum tunnelling devices. Potential reasons for the instabilities in the I-V characteristics are discussed.