Wide InP Nanowires with Wurtzite/Zincblende Superlattice Segments Are Type-II whereas Narrower Nanowires Become Type-I: An Atomistic Pseudopotential Calculation

Nanowire-superlattices with different structural phases along the nanowire direction, such as wurtzite (WZ) and zincblende (ZB) forms of the same compound, often exhibit a "type II" band-alignment with electrons on ZB and holes on WZ. This is a material property of most of III-V semiconductors. We show via InP nanowires that as the nanowire diameter decreases, quantum-confinement alters this basic material property, placing both electrons and holes on the same (ZB) phase. This structural design causes a dramatic increase in absorption strength and reduced radiative lifetime.