Two-Dimensional Energy Band Engineering in GaAs/AlGaAs Core–Shell Nanowires by Crystal-Phase Switching for Charge Manipulation

Two-dimensional (2D) band engineering within nanowires is realized by axial switching of crystal-phase from wurtzite to zinc blende and a lateral GaAs/AlGaAs core–shell structure. Band alignment between different phases/materials is investigated through off-axis electron holography and interpolation calculations, which is further utilized for controlling the migration of carriers. Besides, the arrangement of the heterophase layers is found to affect the charge distribution severely. Above all, carrier reservoirs and a charged surface/interface could be achieved within a single nanowire by 2D band engineering. Our work offers a new idea on the construction of nanostructures for applications in photoelectric and electronic domains.