Electronic structures of wurtzite GaAs nanowires in the  direction were studied using first-principles calculations. It was found that the band gap of GaAs nanowires experiences a direct-to-indirect transition when the diameter of the nanowires is smaller than ∼28 Å. 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.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)