Band structure of segmented semiconductor nanowires

摘要

We have calculated the band structures for strained segmented nanowires involving all combinations of AlN, GaN, InN, AlP, GaP, AlAs, GaAs, InP, InAs, AlSb, GaSb, and InSb, as a function of segment length. This was done for two different growth directions of the wires, [100] and [111]. Both the Γ and the X conduction-band minima were included in the calculations as well as the valence bands. Short segments behave like strained quantum wells and our results thus include strained quantum wells as a subset. We find all material combinations that give metallic segments due to a negative band gap and we find all the band alignments that may occur. We identify those structures which show spontaneous charge separation as well as those which are suitable for the optical generation of polarized exciton gases, with their rich phase diagram, theoretically predicted to include superfluids and supersolids. Some device related ideas are presented. Due to the amount of data (several hundreds of diagrams) most of our results are presented as a webpage.