High mobility back-gated InAs/GaSb double quantum well grown on GaSb substrate

TL;DR

This paper presents a high-mobility InAs/GaSb double quantum well device grown on GaSb substrate, demonstrating high-quality material properties and quantum Hall effects, advancing the development of quantum electronic devices.

Contribution

The study introduces a high-mobility InAs/GaSb quantum well device grown directly on GaSb substrate, enabling efficient back gating and observation of quantum Hall effects.

Findings

Electron mobility exceeds 500,000 cm²/Vs

Quantum Hall effects observed in electron and hole regimes

High-quality lattice matching without thick buffer layers

Abstract

We report a backgated InAs/GaSb double quantum well device grown on GaSb substrate. The use of the native substrate allows for high materials quality with electron mobility in excess of 500,000 cm2/Vs at sheet charge density of 8x1011 cm-2 and approaching 100,000 cm2/Vs near the charge neutrality point (CNP). Lattice matching between the quantum well structure and the substrate eliminates the need for a thick buffer, enabling large back gate capacitance and efficient coupling with the conduction channels in the quantum wells. As a result, quantum Hall effects are observed in both electron and hole regimes across the hybridization gap.