Edgeless and Purely Gate-Defined Nanostructures in InAs Quantum Wells

TL;DR

This paper introduces a novel electrostatic gating technique to create nanostructures like quantum point contacts and quantum dots in InAs quantum wells without traditional etching, overcoming parasitic conduction issues.

Contribution

The authors demonstrate a purely gate-defined approach for fabricating nanostructures in InAs quantum wells, avoiding etching and related parasitic effects.

Findings

Successful realization of quantum point contacts with full pinch-off.

Observation of Coulomb-blockade diamonds in quantum dots.

Effective multi-layer gating to control nanostructures.

Abstract

Nanostructures in InAs quantum wells have so far remained outside of the scope of traditional microfabrication techniques based on etching. This is due to parasitic parallel conduction arising from charge carrier accumulation at the physical edges of samples. Here we present a technique which enables the realization of quantum point contacts and quantum dots in two-dimensional electron gases of InAs purely by electrostatic gating. Multiple layers of top gates separated by dielectric layers are employed. Full quantum point contact pinch-off and measurements of Coulomb-blockade diamonds of quantum dots are demonstrated.