Type-II induced quantum confinement in type-I heterostructured semiconductor nanowires

We theoretically investigate the electronic properties of semiconductor nanowires with axial heterostructure. We employ the effective mass approximation within envelope wavefunction formalism to analyze the behavior of charge carriers in nanowires composed of two semiconductor materials with different energy gaps, grown along the wire axis, with a cylindrically symmetric shape. We start by considering a type-I band alignment, resulting in the formation of a quantum well structure. Then, we demonstrate that modifications in the effective mass and the structural parameters of the system make it possible to change the type of the band alignment, thus dictating the carrier confinement. For certain values of the wire radius and the ratio of effective masses between the well and barrier regions, the contribution of the kinetic energy term to the total effective confinement potential becomes predominant compared to the mismatched band potential. This leads to a switching in the preferential spatial distribution of the wave functions towards the barrier region, exhibiting characteristics of a type-II induced axial junction.