Electronic structures of zigzag AlN, GaN nanoribbons and Al xGa 1− xN nanoribbon heterojunctions: First-principles study

Abstract

The electronic and structural properties of zigzag aluminum nitride (AlN), gallium nitride (GaN) nanoribbons and Al x Ga 1− x N nanoribbon heterojunctions are investigated using the first-principles calculations. Both AlN and GaN ribbons are found to be semiconductor with an indirect band gap, which decreases monotonically with the increased ribbon width, and approaching to the gaps of their infinite two dimensional graphitic-like monolayer structures, respectively. Furthermore, the band gap of Al x Ga 1− x N nanoribbon heterojunctions is closely related to Al (and/or Ga) concentrations. The Al x Ga 1− x N nanoribbon of width n=8 shows a continuously band gap varying from about 2.2 eV–3.1 eV as x increases from 0 to 1. The large ranged tunable band gaps in such a quasi one dimension structure may open up new opportunities for these AlN/GaN based materials in future optoelectronic devices.