Structural and Electronic Properties of Defective AlN/GaN Hybrid Nanostrutures

Due to the wide range of possible applications, atomically thin two-dimensional heterostructures have attracted much attention. In this work, using first-principles calculations, we investigated the structural and electronic properties of planar AlN/GaN hybrid heterojunctions with the presence of vacancies at their interfaces. Our results reveal that a single vacant site, produced by the removal of Aluminum or Gallium atom, produces similar electronic band structures with localized states within the bandgap. We have also observed a robust magnetic behavior. A nitrogen-vacancy, on the other hand, induces the formation of midgap states with reduced overall magnetization. We have also investigated nanotubes formed by rolling up these heterojunctions. We observed that tube curvature does not substantially affect the electronic and magnetic properties of their parent AlN/GaN heterojunctions. For armchair-like tubes, a transition from direct to indirect bandgap was observed as a consequence of changing the system geometry from 2D towards a quasi-one-dimensional one. The magnetic features presented by the AlN/GaN defective lattices make them good candidates for developing new spintronic technologies.