Subsurface imaging of coupled carrier transport in GaAs/AlGaAs core-shell nanowires

Abstract

We demonstrate spatial probing of carrier transport within GaAs/AlGaAs core-shell nanowires with nanometer lateral resolution and subsurface sensitivity by energy-variable electron beam induced current imaging. Carrier drift that evolves with applied electric field is distinguished from a coupled drift-diffusion length. Along with simulation of injected electron trajectories, combining beam energy tuning with precise positioning for selective probing of core and shell reveals axial position- and bias-dependent differences in carrier type and transport along parallel conduction channels. These results indicate how analysis of transport within heterostructured nanomaterials is no longer limited to nonlocal or surface measurements.