Ab Initio Study of Confinement and Surface Effects in AlN Nanowires

作者：Rezouali K; Belkhir M A^*; Bai J B

来源：Journal of Physical Chemistry C, 2010, 114(26): 11352-11357.

DOI：10.1021/jp100024m

Electronic structures and imaginary parts of dielectric functions of AlN nanowires are calculated using density functional theory. It is found that the surface atoms form quite localized states near the top of the valence band and the bottom of the conduction band. The dielectric function spectrum of a AlN nanowire is shown to be correlated with the surface-to-volume ratio. As the number of surface atoms to the bulk atoms decreases, the optical absorption of a AlN nanowire gradually acquires bulklike features. Furthermore, the effect of piezoelectric field on the AlN nanowire optical properties are tested. It is found that in addition to the shifts toward higher energies, as it is usual in bulk AlN, one can also obtain shifts toward lower energies depending on the frequencies. As the diameter of the nanowire increases, the reversal becomes less pronounced suggesting that the optical transition of a realistic AlN nanowire most probably manifests under stress a shift toward higher energies.

• 出版日期2010-7-8