In-situ electron-beam lithography of deterministic single-quantum-dot mesa-structures using low-temperature cathodoluminescence spectroscopy

TL;DR

This paper presents a precise in-situ electron-beam lithography technique using low-temperature cathodoluminescence spectroscopy to fabricate deterministic single-quantum-dot mesa-structures with high optical quality.

Contribution

It introduces a novel two-step lithography process combining CL spectroscopy and electron-beam lithography for deterministic quantum dot device fabrication.

Findings

High optical quality of quantum dot structures with linewidths below 15 ueV.

Alignment precision better than 100 nm achieved.

Demonstrated potential for fully deterministic quantum device fabrication.

Abstract

We report on the deterministic fabrication of sub-um mesa structures containing single quantum dots by in-situ electron-beam lithography. The fabrication method is based on a two-step lithography process using a low-temperature cathodoluminescence (CL) spectroscopy setup. In the first step the position and spectral features of single InGaAs quantum dots (QDs) are detected by CL. Then circular sub-um mesa-structures are exactly defined by high-resolution electron-beam lithography and subsequent etching in the second step. CL spectroscopy and micro-photoluminscence spectroscopy demonstrate the high optical quality of the single-QD mesa-structures with emission linewidths below 15 ueV and g(2)(0) = 0.04. Our lithography method allows for an alignment precision better than 100 nm which paves the way for a fully-deterministic device technology using in-situ CL lithography.