Investigation of the electronic transport in GaN nanowires containing GaN/AlN quantumdiscs

Abstract

We report the investigation of electronic transport in GaN nanowires containingGaN/AlN quantum discs (QDiscs). The nanowires were grown by plasma-assistedmolecular beam epitaxy and contacted by electron-beam lithography. Three nanowiresamples containing QDiscs are analyzed and compared to a reference binary n–i–nGaN nanowire sample. The current–voltage measurements on single nanowiresshow that if the QDiscs are covered with a lateral GaN shell, the current mainlyflows through the shell close to the lateral surface and the wire conductivity isextremely sensitive to the environmental conditions. On the contrary, if no GaNshell is present, the current flows through the QDisc region and a reproduciblenegative differential resistance related to electron tunneling through the QDiscs canbe observed for temperatures up to 250 K. The demonstration of the resonanttunneling in GaN/AlN superlattices is of major importance for the development ofnitride-based far-infrared quantum cascade lasers operating at high temperature.