Controlling Phase‐Coherent Electron Transport in III‐Nitrides: Toward Room Temperature Negative Differential Resistance in AlGaN/GaN Double Barrier Structures

Resonant tunneling of electrons is important for the manufacture of high‐speed electronic oscillators and the electron injection control in quantum cascade lasers. In this work, room temperature negative differential resistance (NDR) in AlGaN/GaN double barrier structure with AlN/GaN digital alloy (DA) barriers is demonstrated. The peak‐to‐valley current ratio (PVCR) ranges from 1.1 to 1.24 at room temperature and becomes 1.5 to 2.96 at low temperatures, whereas no NDR is observed in double barrier structures with conventional ternary AlGaN barriers. The room temperature NDR together with the high PVCR at low temperature is attributed to the suppression of alloy disorder scattering by introducing AlN/GaN DA barriers. This work presents the successful control of phase‐coherent electron transport in III‐nitride heterostructures and is expected to benefit the future design of nitride‐based resonant tunneling structures and high‐speed electronic devices. By using AlN/GaN digital alloy barriers, the inelastic electron transport due to alloy disorder scattering is reduced, which enhances the phase‐coherent transport of electrons and leads to room temperature negative differential resistances and large low temperature peak‐to‐valley current ratios in AlGaN/GaN double barrier structures. The results are to benefit the design and fabrication of nitride‐based resonant tunneling devices.