Type-II Ge/Si quantum dots

The electronic structure of spatially indirect excitons, multiparticle exci tonic complexes, and negative photoconductivity in arrays of Ge/Si type-II quantum dots (QDs) are considered. A comparison is made with the well-known results for type-II III-V and II-VI QD heterostructures. The following fun damental physical phenomena are observed in the structures under study: an increase in the exciton binding energy in QDs as compared with that for fre e excitons in homogeneous bulk materials, a blue shift in the excitonic tra nsitions during the generation of multiparticle complexes (charged excitons , biexcitons), and the capture of equilibrium carriers to localized states induced by the electric field of charged QDs. (C) 2001 MAIK "Nauka /Interpe riodica".