Tip artifact in atomic force microscopy observations of InAs quantum dots grown in Stranski-Krastanow mode

TL;DR

This study quantitatively evaluates the tip artifact in AFM measurements of InAs quantum dots grown via Stranski-Krastanow mode, enabling more accurate size determination of the islands.

Contribution

It provides a method to correct AFM measurements for tip artifacts and oxide effects, improving the accuracy of quantum dot size estimation.

Findings

AFM measurements overestimate island size due to tip artifact and oxide

TEM measurements provide more accurate island dimensions excluding oxide

Correction factors enable precise determination of true island sizes from AFM images

Abstract

The tip artifact in atomic force microscopy (AFM) observations of InAs islands was evaluated quantitatively. The islands were grown in the Stranski-Krastanow mode of molecular beam epitaxy. The width and height of the islands were determined using transmission electron microscopy (TEM) and AFM. The average $[\bar{1}10]$ in-plane width and height determined using TEM excluding native oxide were 22 and 7 nm, respectively; those determined using AFM including the oxide were 35 and 8 nm, respectively. The difference in width was due to the oxide and the tip artifact. The sizes including the oxide were deduced from TEM observations to be a width of 27 nm and a height of 6 nm with correction for the thickness of the oxide. The residual difference of 8 nm between the width determined using AFM and that determined using TEM including the oxide was ascribed to the tip artifact. The results enable us to determine the actual size of the islands from their AFM images.