Modeling study on the properties of GaN/AlN core/shell nanowires by surface effect suppression

Physical properties of a nano structure are dramatically affected by its surface reconstruction and quantum confinement. For a core/shell structured nanowire (NW), the core/shell interface also plays a key role. The effects induced solely by the surface reconstruction can be estimated by using a reference model in which the dangling bonds on the NW's surface are saturated by a number of pseudo hydrogen atoms with fractional charge. We present in this paper a first principles study on the role of the surface reconstruction in several series of gallium nitride/aluminum nitride core/shell structured NWs. We also show that the model of pseudo hydrogen atoms does suppress the effects of surface reconstruction on both structural and electronic properties of the NWs, thus the model can be used to estimate the role of surface reconstruction.