Gating of high-mobility two-dimensional electron gases in GaAs/AlGaAs heterostructures

TL;DR

This study explores how Schottky gates influence electron density and mobility in high-mobility 2D electron gases in GaAs/AlGaAs heterostructures, revealing in situ tunability of mobility across different configurations.

Contribution

It demonstrates that two different sample configurations can be achieved in situ with significantly different mobilities, highlighting charge redistribution effects.

Findings

Mobility can differ by more than a factor of two between configurations.

Electron density and mobility are gate-dependent.

Charge redistribution impacts heterostructure design.

Abstract

We investigate high-mobility two-dimensional electron gases in AlGaAs heterostructures by employing Schottky-gate-dependent measurements of the samples' electron density and mobility. Surprisingly, we find that two different sample configurations can be set in situ with mobilities diering by a factor of more than two in a wide range of densities. This observation is discussed in view of charge redistributions between the doping layers and is relevant for the design of future gateable high-mobility electron gases.