Negative Differential Resistance in GaN/AlN Heterostructure Nanowires

III-V semiconductor nanowire heterostructures have experienced great progress in numerous mid-and far-infrared ranges. In this work, the electrical properties of GaN/AlN nanowire heterostructures, oriented along the [0001] polar direction and grown vertically on a Si substrate by molecular beam epitaxy, were studied in the context of resonant tunneling. The negative differential resistance was observed in I-V measurements at room temperature and at 78 K for single nanowire devices, confirming the presence of resonant tunneling through AlN barriers. A peak-to-valley ratio of 1.4 was achieved. Effects of different doping profiles have been investigated, showing slight improvement of the resonant tunneling in the presence of silicon doping. This work represents a preliminary step in developing GaN nanowire based intersubband devices for far-infrared and telecom wavelength lasers and photodetectors.