Electronic properties of Ge–Si nanoparticles
Physical and Theoretical Chemistry, University of Saarland, 66123 Saarbrücken, Germany
Revised: 8 September 2006
Published online: 24 May 2007
Using a parameterized density-functional tight-binding method we have calculated the electronic and structural properties of Ge–Si nanoparticles. Starting with a spherical part of a zinc-blende/diamond crystal (with the center of the sphere at the mid-point of a nearest-neighbour bond) we have constructed initial structures that subsequently were allowed to relax. Structures consisting solely of Ge atoms or solely of Si atoms were studied, together with core-shell structures for which one semiconductor forms a shell on the core of the other semiconductor. Moreover, homogeneous, ordered SiGe structures as well as structures with a semisphere of one semiconductor and a semisphere of the other were also considered. In analysing the results special emphasis is put on identifying particularly stable structures, on explaining the occurrence of those, on the spatial distribution of the frontier orbitals, and on the variation of the total energy with structure and composition.
PACS: 36.40.Cg – Electronic and magnetic properties of clusters / 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007