ABSTRACT

This chapter presents complementary quantitative techniques for the direct morphology and compositional analysis of quantum dots (QDs), in which scanning transmission electron microscopy and high-resolution in plane X-ray scattering are applied to a buried InAs/GaAs QD layer in a structure containing InxGa1-xAs/GaAs quantum well layers to provide an internal calibration of the In content. The electronic properties of QDs essentially depend on the perfection of the active elements such as the size, shape, arrangement, crystal morphology and composition. For device applications, the real interest for structures with QDs is concerned with buried dots, for example in an optically reflecting cavity provided by periodic multilayers. The quantitative compositional analysis across the full length of QDs can be performed on the cross-sectional specimens. The analysis of different QD structures corresponding to the various stages of their formation and fabrication towards the final optoelectronical devices was carried out to gain an understanding of the mechanism and control of QD formation.