Low-density high-mobility electron gas in wide parabolic GaAs/AlxGa1−xAs wells

Abstract
Remotely doped wide parabolic GaAs/AlxGa1−xAs wells are used to create thick (≳ 1000 Å) layers of high‐mobility (≳ 2×105 cm2/V s) electron gas with three‐dimensional densities below (by a factor ∼3) the metal‐insulator transition for doped GaAs. The temperature dependences of the Hall mobility and sheet density show no qualitative changes in a series of three samples spanning the metal‐insulator transition. Shubnikov–de Haas oscillation measurements are used to determine the width of the electron gas layers.