Investigation of the negative differential resistance reproducibility in AlN/GaN double-barrier resonant tunnelling diodes

AlN/GaN double-barrier resonant tunnelling diodes were grown by molecular beam epitaxy on GaN/sapphire template and processed into mesa diameters from 2 mu m to 4 mu m. The current-voltage characteristics were carried out in direct current operation and under-high vacuum. A sharp negative differential resistance (NDR) was detected in the forward bias at 120 K. The NDR was observed for the mesa size of 2 mu m at 4V with a peak-to-valley current ratio of 3.5. The measurement conditions were chosen to make NDR reproducible more than 50 times and apparent in both scan voltage directions after electrical treatment. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3659468]