TEM nanoscale analysis of InAs quantum dots grown on GaAs by MBE

摘要

We report the application of various high resolution and analytical transmission electron microscopy (TEM) techniques to study the microstructural properties of self-assembled InAs dots formed in a GaAs(001) matrix. Two samples grown under otherwise identical conditions but with different growth rates have been studied. TEM measurements of the dot densities, compositions and morphologies were performed and the results compared with optical measurements of the same samples. The lower ground state emission energy observed for the slow growth rate sample supports TEM results which show that these dots are taller than those grown with the fast growth rate. The dot density is found to increase with growth rate; consistent with a similar observation for uncapped samples. The use energy dispersive spectroscopy (EDS) techniques enables the dot composition profiles to be deduced.