High-Mobility Two-Dimensional Electron Gas in an Undoped Heterostructure: Mobility Enhancement after Illumination

Abstract
High-mobility two-dimensional electron gas (2DEG) is formed at an undoped GaAs/AlGaAs inverted heterointerface through the field-effect using a back-gate. Despite the structure being undoped, mobility enhancement is observed at 1.6 K after illumination. This suggests effective reduction of background impurity scattering by illumination. The maximum mobility reached after illumination, 5×106cm2/V·s, is the highest value ever reported for gated undoped heterostructures, including both normal- and inverted-type structures. This mobility is also the highest ever reported for inverted GaAs/AlGaAs heterostructures.