Structural and electronic properties of [0001] AIN nanowires: A first-principles study

Using first- principles methods, we investigated the atomic relaxations, electronic structure, and formation energies of nonpassivated A1N nanowires along [0001] directions. We find that all the nanowires prefer to have (101 (1) over bar0) lateral facets and all the wires with (10 (1) over bar0) lateral facets are semiconductors with a direct band gap. However, surface states that arise from the facet atoms exist inside the bulklike band gap, which can have a large effect on the optoelectronic properties of the nanowires. Our calculated formation energies of the nanowires show that there is a sublinear relationship between the formation energy and surface- to- volume ratio, indicating that the surface effect is localized and becomes more important for small nanowires. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3003528]