Quantum dot defined by local top-gates along InAs/AlOx core-shell nanowire

Abstract

Quantum dots formed in InAs semiconductor nanowires are believed to provide a platform for spin-based quantum dot (QD) device due to its large spin-orbit coupling strength. For coherent manipulation of such quantum device, reliable local gate control is required to tune the coupling strength between the QD and contact electrodes. In this work, we developed single electron transistor using InAs/AlOx core-shell structured nanowire. AlOx layer is deposited as an insulating layer on as-grown InAs semiconducting nanowire by the well-known atomic layer deposition (ALD) technique. QD is defined by local top-gates along the nanowire. Combined control of local and global gates allows us to tune local tunnel barrier heights between the QD and contact electrodes. This is elucidated by Coulomb-diamond patterns in conductance-density map as a function of source-drain and gate voltages at 4.2 K.