Quantitative measurements of the inhomogeneous strain field of stacked self-assembled InAs/InP(001) quantum wires by the Peak Finding Method

摘要

Stacks of InAs self-assembled quantum wires (QWr) grown by solid source molecular beam epitaxy on InP (001) substrates have been studied by both transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Samples with an InP spacer layer thickness ≤ 10 nm are shown to exhibit stacked quantum wires well arranged along directions close to [001]. The analysis of some HRTEM images by the Peak Finding Method demonstrates the existence of an inhomogeneous strain field distribution throughout the InP spacer layers. The growth front of the InP spacer layers shows the lowest stress for the growth of further InAs wires on the areas located on top of each buried wire. The InAs wires are preferentially formed on these lowest stress surface areas.