Physical properties of highly uniform InGaAs pyramidal quantum dots with GaAs barriers: Fine structure splitting in pre-patterned substrates

TL;DR

This study investigates the fine structure splitting in highly uniform InGaAs pyramidal quantum dots with GaAs barriers, demonstrating their consistent properties and potential for degeneracy restoration through minor adjustments.

Contribution

The paper provides the first detailed analysis of FSS in pyramidal quantum dots grown in inverted tetrahedral recesses, highlighting their uniformity and suitability for quantum applications.

Findings

FSS values are highly uniform across dots

Average FSS is 13 μeV, with low chance of zero splitting

Degeneracy can be restored with small magnetic fields

Abstract

InGaAs Quantum Dots embedded in GaAs barriers, grown in inverted tetrahedral recesses of 7 {\mu}m edge, have showed interesting characteristics in terms of uniformity and spectral narrowness of the emission. In this paper we present a study on the fine structure splitting (FSS). The investigation of about 40 single quantum dots revealed two main points: (1) the values of this parameter are very similar from dot to dot, proving again the uniformity of Pyramidal QD properties, (2) there is a little chance, in the sample investigated, to find a dot with natural zero splitting, but the values found (the mean being 13 {\mu}eV) should always guarantee the capability of restoring the degeneracy with some corrective technique (e.g. application of a small magnetic field).