Complementary application of Raman scattering and GISAXS in characterization of embedded semiconductor QDs

Here we report the comparative analysis of Raman scattering and Grazing incidence small angle scattering of X-rays (GISAXS) applied on the systems of Ge and II-VI compound quantum dots (QDs) embedded in dielectric matrix. In Raman scattering, the synthesis of QDs, their phase and composition, as well as crystal quality, were determined by analyzing the material-related characteristic optical phonon modes. Additionally, from the analysis of the low frequency vibrational Raman band, the size and size distribution of nanoparticles were calculated. GISAXS was applied to study the synthesis of QDs through a proper analysis and modeling of the corresponding 2D spectra. The QD sizes were determined by a Guinier-plot analysis, whereas the Local Monodisperse Approximation (LMA) was used for the analysis of the shape and the size as well as size distribution. We have demonstrated that Raman and GISAXS give complementary results indispensable for the complete characterization of such systems. The results are to be used for further improvements of semiconductor QD preparation.