Band alignment of zincblende and wurtzite AlGaAs

Determine the band alignment between the zincblende and wurtzite phases in AlGaAs to enable accurate modeling and design of AlGaAs crystal-phase quantum dots and related nanowire devices.

Background

Crystal-phase quantum dots in AlGaAs nanowires are formed by zincblende insertions within a wurtzite AlGaAs nanowire. Their electronic and optical behavior depends critically on whether the phase boundary produces type-I or type-II band alignment, because this determines the spatial distribution of electrons and holes, exciton lifetimes, radiative recombination rates, and sensitivity to charge noise.

The paper infers type-I alignment from the approximately 1 ns exciton lifetime, large exciton fine-structure splitting, and observed Zeeman splitting. However, the authors explicitly state that the band alignment between the zincblende and wurtzite phases in AlGaAs had not previously been predicted or measured. Establishing this alignment remains important for quantitatively modeling the quantum dots and optimizing their dimensions and device applications. The authors further note that core diameter may affect the alignment through radial quantum confinement, potentially inducing a type-II-to-type-I transition.