Isolated conductance channels inside the bandgap of GaAs nanowires of zincblende and wurtzite heterostructures

Abstract

Electronic properties of polytypes (i.e., the co-existence of zincblende and wurtzite structures in III–V compound semiconductor nanowires) are still highly controversial. In an effort to explore fundamental insights of this topic, we investigate the electronic conductance for GaAs nanowires having arbitrary sequence of zincblende and wurtzite heterostructures by a five-nearest-neighbor tight-binding model. The transmission function χ(E) of the zincblende–wurtzite heterostructure is calculated in the mixture from the complete zincblende to the complete wurtzite configuration by non-equilibrium Green’s function formulae. The properties of the ballistic conductance of the system are analyzed by convolving χ(E) with the thermal broadening function. Numerical results show that more inclusion of the wurtzite-type segments into the GaAs nanowires can establish isolated conductance channels in the neighborhood of the bandgap edge, providing potential optoelectronic applications for mid-infrared optics.