Charge control in laterally coupled double quantum dots

TL;DR

This study explores how lateral electric fields influence the electronic and optical behaviors of InAs double quantum dots, demonstrating control over electron confinement and revealing tunneling effects through emission spectrum analysis.

Contribution

It introduces a method to control electron charge states in double quantum dots using lateral electric fields and explains the reversed trion emission ordering via tunneling effects.

Findings

Electron confinement can be tuned with external bias.

Reversed trion emission lines are explained by quantum tunneling.

Lateral electric fields affect optical emission spectra.

Abstract

We investigate the electronic and optical properties of InAs double quantum dots grown on GaAs (001) and laterally aligned along the [110] crystal direction. The emission spectrum has been investigated as a function of a lateral electric field applied along the quantum dot pair mutual axis. The number of confined electrons can be controlled with the external bias leading to sharp energy shifts which we use to identify the emission from neutral and charged exciton complexes. Quantum tunnelling of these electrons is proposed to explain the reversed ordering of the trion emission lines as compared to that of excitons in our system.