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

Under the generalized gradient approximation (GGA), the stabilities and electronic properties of semiconductor AlN nanostructures have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The single-walled faceted AlNNTs present an obvious structural modification. The larger the diameter, the more stable the nanowire, and the wires without internal surfaces are more stable than the multiwalled tubes or the SWNT. Therefore, the large-size nanowires are easier to be synthesized than the corresponding multiwalled tubes or single-walled nanotube in experiment. The dangling bonds of surface atoms cause the “localized edge-induced states”. These two nanostructures C and F are still wide band gap semiconductors accompanied by a few surface states located in the band gap of bulk AlN and thus extremely suitable for application in flexible pulse wave sensors, nanomechanical resonators and light-emitting diodes.

► The single-walled faceted AlNNTs present an obvious structural modification.
► The most stabilized nanowire and faceted nanotube are the C and F, respectively.
► These two nanostructures C and F are still wide band gap semiconductors.
► A few surface states of the C and F locate in the band gap of bulk AlN.
► The dangling bonds of surface atoms cause the “localized edge-induced states”.