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

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 [110] 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.

Influence of quantum dots shape approximation on size reconstructed from atomic force microscopy measurements

“…These results indicate that ignoring the shape of the tip and/or the objects may lead to significant errors in estima− tion of the dimension of observed objects. The results shown here explain the differences between results obtained by AFM and TEM [7].…”

“…This is due to the fact that the dimensions of objects are comparable to the ra− dius of the probe tip R and therefore determined dimensions may differ considerably from the actual sizes. These tip re− lated artifacts in observations of nanostructures result in dif− ferences between the results obtained with TEM and AFM measurements [7]. However, with a majority of solids the heights measured by AFM can be considered to represent the true values, providing the calibration is correct.…”

Low-Dimensional Group III-V Compound Semiconductor Structures

“…1. 42 Semiconductor 3D islands, at least those drawing significant attention with the hope of superior optoelectronic devices in the last decade, are expected to exhibit unique physical characteristics associated with their unique features such as shape, size and electronic structures. Among various semiconductor 3D islands, two material systems; silicon/germanium grown on silicon surfaces and indium arsenide (InAs) grown on gallium arsenide (GaAs) surfaces have been used as convenient vehicles for extensive study because of their inherent simplicity (e.g., chemical composition).…”

“…The width and height of the island are 27 and 9 nm, respectively. 42 Comprehensive reviews in the field of 3D islands (also referred to as quantum dots) are available. 43 In the following section, a series of studies on InAs 3D islands grow on GaAs substrates are described by focusing on three topics; two-dimensional to three-dimensional morphological transition, lateral size equalization, and vertical alignment of an ensemble of 3D islands, all of which are crucially important issues that need to be addressed in the course of implementation of ensembles of 3D islands as a part of solid-state devices.…”

Development of Si/SiO₂ Multilayer Type AFM Tip Characterizers

“…At the same time, tip characterizers have also been reported. Spherical structures such as colloidal gold [4], polystyrene or glass spheres [5,6], nanofabricated spheres [7], hole grid patterns [8], quantum dots [9], dot grid patterns [10], needle-shaped samples [11] and other nanostructures [12] have been demonstrated. However, it is difficult to evaluate the fine shape of an AFM tip, especially that of the sides.…”