High resolution analysis of embedded quantum dots

摘要

A key piece of information in the understanding of quantum dot behaviour is the composition of the dot after any capping and/or annealing processes. It is important to know the composition and uniformity of the dots after they have been embedded in a semiconducting matrix, which usually contains one or more of the elements in the dot. This is a classically difficult analytical problem for any TEM technique. This problem has been approached by developing a model of the interaction between the electron probe and any dot/wetting-layer/matrix configuration. This model predicts the shape of an analytical line scan for any particular configuration and includes the effect of beam broadening on the analysis of dots at different depths within the thin section. The results are compared with STEM analyses of InAs dots in a GaAs matrix.