Charge distribution and vertical electron transport through GaN/AlN/GaN single-barrier structures

Abstract

We investigate the charge distribution and vertical electron transport through GaN/AlN/GaN single-barrier structures with different AlN thickness. The results of electrical characterization are interpreted by comparison with simulations of the electronic structure using a self-consistent Schrödinger–Poisson equation solver. Capacitive measurements confirm the formation of a two-dimensional electron gas at the bottom interface of the AlN barrier, even for barrier thickness of 0.5 nm. Conductive atomic force microscopy reveals that the current flow concentrates at discrete locations whose density is in the 107 cm−2 range, more than one order of magnitude lower than the dislocation density in these samples.