Crystal defect topography of Stranski-Krastanow quantum dots by atomic force microscopy

We demonstrate a technique to monitor the defect density in capped quantum dot (QD) structures by performing an atomic force microscopy (AFM) of the final surface. Using this method we are able to correlate their density with the optical properties of the dot structures grown at different temperatures. Parallel transmission electron microscopy analysis shows that the AFM features are directly correlated with the density of stacking faults that originate from abnormally large dots. The technique is rapid and noninvasive making it an ideal diagnostic tool for optimizing the parameters of practical QD-based devices.