1208.1246 (Andrew Copple et al.)

Engineering direct-indirect band gap transition in wurtzite GaAs
nanowires through size and uniaxial strain    [PDF]

Andrew Copple, Nathaniel Ralston, Xihong Peng

Electronic structures of wurtzite GaAs nanowires in the [0001] direction were studied using first-principles calculations. It was found that the band gap of GaAs nanowires experience a direct-to-indirect transition when the diameter of the nanowires is smaller than ~28 {\AA}. For those thin GaAs nanowires with an indirect band gap, it was found that the gap can be tuned to be direct if a moderate external uniaxial strain is applied. Both tensile and compressive strain can trigger the indirect-to-direct gap transition. The critical strains for the gap-transition are determined by the energy crossover of two states in conduction bands.

View original: http://arxiv.org/abs/1208.1246