Size dependent exciton g-factor in self-assembled InAs/InP quantum dots

TL;DR

This study investigates how the exciton g-factor varies with size in self-assembled InAs/InP quantum dots, revealing a strong size dependence and sign change, supported by experimental measurements and theoretical calculations.

Contribution

It provides the first systematic analysis of size-dependent exciton g-factor and anisotropy splitting in InAs/InP quantum dots using combined photoluminescence and microscopy techniques.

Findings

Exciton g-factor varies significantly with quantum dot size.

A sign change in the g-factor occurs with increasing size.

Size-dependent anisotropy splitting observed at zero magnetic field.

Abstract

We have studied the size dependence of the exciton g-factor in self-assembled InAs/InP quantum dots. Photoluminescence measurements on a large ensemble of these dots indicate a multimodal height distribution. Cross-sectional Scanning Tunneling Microscopy measurements have been performed and support the interpretation of the macro photoluminescence spectra. More than 160 individual quantum dots have systematically been investigated by analyzing single dot magneto-luminescence between 1200nm and 1600 nm. We demonstrate a strong dependence of the exciton g-factor on the height and diameter of the quantum dots, which eventually gives rise to a sign change of the g-factor. The observed correlation between exciton g-factor and the size of the dots is in good agreement with calculations. Moreover, we find a size dependent anisotropy splitting of the exciton emission in zero magnetic field.