Plan-view HAADF-STEM image of the QD layer on a fractured quantum well used in the study. The inset shows a magnified EDX image of the center region, where a QD with a high compositional contrast to the surrounding material can be seen. The lateral size of the QD is on the order of 20 nm. Note that the value of the indium atomic percentage presented in the figure inset is measured as a projection through the surrounding barrier material and therefore does not accurately represent the absolute value of the material in the QD.