AlN/GaN/AlN resonant tunneling diodes grown by rf-plasma assisted molecular beam epitaxy on freestanding GaN

The authors report the growth by rf-plasma assisted molecular beam epitaxy of AlN/GaN/AlN resonant tunneling diodes which exhibit stable, repeatable, and hysteresis-free negative differential resistance (NDR) at room temperature for more than 1000 bias sweeps between −2.5 and +5.5 V. The device layers were grown on freestanding, Ga-polar GaN substrates grown by hydride vapor phase epitaxy and having a density of threading dislocations between 106 and 107 cm−2. The authors speculate that the repeatable NDR is facilitated by the low-dislocation density substrates.