Real-time growth assessments of size orientation and facet asymmetries of self-assembled quantum dots

Structural characteristics of self-assembled quantum dots affect their properties and hence precise knowledge of dot shapes and distributions are of importance to the development of many advanced photovoltaic device concepts employing quantum dots. . For a precise control over dot parameters, reflection high energy electron diffraction (RHEED) has shown to be a reliable analytical tool in extracting dot size and shape in real time span. In this work, we expanded RHEED analysis to study dot parameters at the onset of dot formation to understand growth kinetics at lower InAs coverage. Formation of new facets at initial growth stages were observed and, furthermore, asymmetric dot facet ripening in smaller QDs were also noted.