First-principles studies on stabilities and electronic properties of AlN nanostructures

Orientation- and passivation-dependent stability and electronic properties of α-Si3N4nanobelts

“…However, in contrast to unpassivated nanobelts, passivated ones exhibit semiconducting characteristics. This feature originates from the dangling bonds on the facets of unpassivated nanobelts appearing in the band-gap region of the bulk a-Si 3 N 4 , which is similar to that of other 1D nanostructures, such as AlN nanowires 31 and SiC nanowires. 36 The quantum confinement effects do not always result in a direct band gap for all a-Si 3 N 4 nanobelts.…”

“…Therefore, theoretical studies are important for better understanding of the micro mechanisms and the relationship between the properties of 1D nanostructures and their structures. In fact, the stability and electronic structures for other 1D nanomaterials, such as SiC nanowires (SiCNWs), ZnO nanowires (ZnONWs), Si nanowires (SiNWs), AlN nanowires (AlNNWs) possessing different growth directions, diameters, and surface functionalization, [27][28][29][30][31] have been extensively investigated by first-principles calculations within DFT. Wang et al 27 show that the SiCNWs along the [111] direction with the zinc blende form are energetically most favorable, which is in good agreement with the experimental results.…”

“…It should be also noted that the quantum confinement effects do not always result in a direct band gap for nanowires, for example, 3C-SiCNWs orientating along the [112] direction have an indirect band gap. 27 For the unpassivated wire, some nanostructures are still wide band gap semiconductors with smaller band gaps than that of the bulk counterparts, 31 whereas some nanostructures are metalized with the surface states crossing the Fermi energy. 35,36 In addition, the large surface-to-volume ratio in 1D nanomaterials can be exploited in functionalization and greatly affects the properties of nanostructures, such as the relative stability 37 and the electronic properties.…”

Hexagonal AlN: Dimensional-crossover-driven band-gap transition

“…In the early study of Du et al, energetic and electronic properties of one-dimensional AlN nanostructures such as nanowires with hexagonal cross sections, double-and triple-walled faceted nanotubes, and single-walled faceted AlN nanotubes were investigated [38]. Between the first theoretical prediction and the experimental realization of h-AlN, other groups have also focused on this material.…”

“…Following the first theoretical study on the stability of hexagonal AlN reported by Sahin et al, 36 successful experimental realization of hexagonal AlN phase was achieved very recently by Tsipas et al 37 In the early study of Du et al, energetic and electronic properties of one-dimensional AlN nanostructures such as nanowires with hexagonal cross sections, double-and triple-walled faceted nanotubes and single-walled faceted AlN nanotubes were investigated. 38 Between the first theoretical prediction and the experimental realization of h-AlN, other groups have also focused on this material. Zheng et al 39 predicted that zigzag AlN nanoribbons have an indirect bandgap whereas armchair AlN nanoribbons have a direct bandgap, and these bandgaps monotonically decrease with increasing ribbon width.…”