Bidirectional negative differential resistance in AlN/GaN resonant tunneling diodes grown on freestanding GaN

In this paper, we report bidirectional negative differential resistance (NDR) in Al(Ga)N/GaN/AlN resonant tunneling diodes grown on free-standing GaN substrates by RF-plasma assisted molecular beam epitaxy. Bidirectional NDR has exhibited a current–voltage (I–V) characteristic in both forward and reverse biases at room temperature. The positive peak current density is 160 kA/cm2 with a peak to valley current ratio (PVCR) of 1.34, and the negative peak current density is 112 kA/cm2 with a high PVCR of 1.56. The bidirectional NDR is attributed to the change in the polarization field in the active region, which is caused by the asymmetric barrier component.