Effects of surface modifications on band gaps and electronic states of GaN/InN core/shell nanowires

Using density-functional theory, we investigate the effects of surface modifications on electronic properties of GaN/InN core/shell nanowires (CSNWs) with different core radii and shell thicknesses in triangular and hexagonal shapes. Our calculations demonstrate that surface modifications with H and F substantially modulate the band gaps and induce the separation of electrons and holes. The results elucidate that surface modifications change electronic structures of CSNWs with a transition from type-I band alignment to quasi-type-II, which could open a new way in the field of renewable energy applications.

The distribution of the LUMO states (upper panel) and HOMO states (lower panel) in hexagonal GaN/InN core/shell nanowires (a) without surface modification, (b) with hydrogenation, and (c) with hydrogenation and fluorination. The small (dark blue), middle (light pink), and large (green) spheres represent N, Ga and In atoms, respectively. The smallest light gray spheres and larger light blue spheres on the surface represent H and F atoms.195Highlights► Surface modifications affect electronic properties of GaN/InN nanowires (NWs). ► Surface modifications with H and F modulate band gaps. ► Surface modifications with H and F induce separation of electrons and holes. ► Surface modifications induce a transition from type-I to quasi-type-II. ► GaN/InN NWs with surface modifications can be applied in renewable energy field.