A semiconductor exciton memory cell based on a single quantum nanostructure

TL;DR

This paper demonstrates a novel exciton memory cell using a single quantum nanostructure, achieving over 30 milliseconds of storage time by controlling electron-hole separation with an electric field.

Contribution

It introduces a semiconductor exciton memory cell based on a single quantum post, showcasing controlled storage and retrieval of excitons in a nanostructure.

Findings

Storage times exceeding 30 milliseconds demonstrated.

Electron tunneling identified as main loss mechanism.

Electric field switching enables exciton reconversion.

Abstract

We demonstrate storage of excitons in a single nanostructure, a self-assembled Quantum Post. After generation electron and holes forming the exciton are separated by an electric field towards opposite ends of the Quantum Post inhibiting their radiative recombination. After a defined time such spatially indirect excitons are reconverted to optically active direct excitons by switching the electric field. The emitted light of the stored exciton is detected in the limit of a single nanostructure and storage times exceeding 30 msec are demonstrated. We identify a slow tunneling of the electron out of the Quantum Post as the dominant loss mechanism by comparing the field dependent temporal decay of the storage signal to models for this process and radiative losses.