Undoped Electron-Hole Bilayers in a GaAs/AlGaAs Double Quantum Well

TL;DR

This paper details the fabrication and characterization of undoped GaAs/AlGaAs electron-hole bilayer devices with independently tunable densities and high mobilities, enabling advanced studies of electron-hole interactions.

Contribution

It introduces a novel undoped double quantum well structure with independent control of electron and hole densities and high mobility, suitable for exploring electron-hole physics.

Findings

Balanced densities from 1.2×10^{11}cm^{-2} to 4×10^{10}cm^{-2} at 300 mK

Electron mobility exceeds 1×10^{6}cm^{2}/V·s

Hole mobility exceeds 4×10^{5}cm^{2}/V·s

Abstract

We present the fabrication details of completely undoped electron-hole bilayer devices in a GaAs/AlGaAs double quantum well heterostructure with a 30 nm barrier. These devices have independently tunable densities of the two-dimensional electron gas and two-dimensional hole gas. We report four-terminal transport measurements of the independently contacted electron and hole layers with balanced densities from $1.2 \times 10^{11}$cm$^{-2}$ down to $4 \times 10^{10}$ cm$^{-2}$ at $T = 300 mK$. The mobilities can exceed $1 \times 10^{6}$ cm$^{2}$ V$^{-1}$ s$^{-1}$ for electrons and $4 \times 10^{5}$ cm$^{2}$ V$^{-1}$ s$^{-1}$ for holes.