Multidirectional observation of an embedded quantum dot

The authors succeeded in observing atomic scale images of undamaged single InAs quantum dots (QDs) embedded in the GaAs matrix using high resolution transmission electron microscope equipped with focused ion beam system. The QD can be viewed from multidirections, and a conclusive and comprehensible determination of the size and the shape anisotropy has been realized. Asymmetry of the structural properties has been confirmed between the [110] and [-110] crystal directions. The embedded QD is elongated along the [-110] axis. The strain-field pattern is also asymmetric according to the shape anisotropy. The results will enable the investigation of the exact structure anisotropy influencing the atomlike properties of QDs. (c) 2007 American Institute of Physics.