Electrically Tunable Room‐Temperature Microwave Oscillations in GaN/AlN Triple‐Barrier Resonant Tunneling Diodes

ABSTRACT Resonant tunneling is a quantum mechanical effect that enables electrons to traverse classically forbidden regions of space. The engineering of this quantum effect in wide‐bandgap semiconductors promises important technological benefits as it seamlessly combines ultra‐fast electron transport dynamics with superior power‐handling capabilities. Here, we report the first realization of highly coherent electronic quantum interference and resonant tunneling injection in wide‐bandgap triple‐barrier heterostructures. Enabled by the high structural quality of the GaN/AlN triple‐barrier active region, we observe multiple resonant tunneling peaks and negative differential conductance at room temperature. The robustness of the inter‐well resonant tunneling current is experimentally confirmed via temperature‐dependent electronic transport and the generation of electrically tunable microwave oscillations. These results represent a stepping stone in the engineering of intersubband tunneling transport in wide‐bandgap III‐nitride semiconductors, raising hopes for the realization of intersubband optical amplification and frequency‐modulated resonant tunneling oscillators.