Multidirectional Transmission Electron Microscope Observation of a Single InAs/GaAs Self-Assembled Quantum Dot

We succeeded in observing atomic scale images of undamaged single InAs quantum dots (QDs) embedded in a GaAs matrix using a combined use of high resolution transmission electron microscope (HRTEM) and focused ion beam (FIB) system for the first time. The QD can be viewed from multi directions, and a conclusive and comprehensive interpretation of the size and shape anisotropy has been achieved. Asymmetry of the structural properties has been confirmed between the [110] and [-110] crystallographic directions. The embedded QD is elongated along the [-110] axis. The strain-field pattern is also asymmetric according to the shape anisotropy Our results will enable the investigation of exact structural anisotropy and their influence on the atom like properties of QDs.