Composition profiling InAs quantum dots and wetting layers by atom probe tomography and cross-sectional scanning tunnelling microscopy

TL;DR

This paper compares atom probe tomography and cross-sectional scanning tunnelling microscopy for analyzing InAs quantum dots and wetting layers, demonstrating their complementary strengths and providing a comprehensive understanding of nanostructure composition.

Contribution

It introduces a comparative analysis of APT and XSTM for InAs quantum dots, highlighting their complementary capabilities in nanostructure characterization.

Findings

Both techniques provide consistent indium concentration profiles.

The methods reveal unique features of the quantum dots and wetting layers.

Computational models align with experimental data from both techniques.

Abstract

This study compares cross-sectional scanning tunnelling microscopy (XSTM) and atom probe tomography (APT). We use epitaxially grown self-assembled InAs quantum dots (QDs) in GaAs as an exemplary material with which to compare these two nanostructural analysis techniques. We studied the composition of the wetting layer and the QDs, and performed quantitative comparisons of the indium concentration profiles measured by each method. We show that computational models of the wetting layer and the QDs, based on experimental data, are consistent with both analytical approaches. This establishes a link between the two techniques and shows their complimentary behaviour, an advantage which we exploit in order to highlight unique features of the examined QD material.