Investigation of indirect structural and chemical parameters of GeSi nanoparticles in a silica matrix by combined synchrotron radiation techniques

• Autor(a) principal: Gasperini, A. A. M.
• Data de Publicação: 2012
• Outros Autores: Malachias, A., Fabbris, Gilberto Fernandes Lopes, Kellermann, Guinter, Gobbi, Angelo Luiz, Avendaño Soto, E., Azevedo, Gustavo de Medeiros
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/89685
• topic: Materiais semicondutores; Crescimento de semicondutores; Nanopartículas; Análise química; Espalhamento de raios-x; Estrutura fina estendida de absorção de raios x (EXAFS); Compostos de silício

The formation of GeSi nanoparticles on an SiO2 matrix is studied here by synchrotron-based techniques. The shape, average diameter and size dispersion were obtained from grazing-incidence small-angle X-ray scattering data. X-ray diffraction measurements were used to obtain crystallite sizes and composition via resonant (anomalous) measurements. By using these techniques as input for extended X-ray absorption fine structure analysis, the local composition surrounding the Ge atoms is investigated. Although the results for each of the methods above are commonly analyzed separately, the combination of such techniques leads to an improved understanding of nanoparticle structural and chemical properties. Crucial indirect parameters that cannot be quantified by other means are accessed in this work, such as local strain, the possibility of forming core–shell structures, the fraction of Ge atoms diluted in the matrix (not forming nanoparticles), the amorphous and crystalline Ge fractions, and the relative population of nanoparticles with single and multiple crystalline domains.