Influence of the germanium deposition rate on the growth and photoluminescence of Ge(Si)/Si(001) self-assembled islands

摘要

The growth and photoluminescence of Ge(Si)/Si(001) self-assembled islands are investigated over a wide range of germanium deposition rates v(Ge) = 0.1-0.75 A/s at a constant growth temperature T-g = 600degreesC. Examination of the surface of the grown structures with an atomic force microscope revealed that, for all the germanium deposition rates used in the experiments, the dominant island species are dome islands. It is found that an increase in the deposition rate v(Ge) leads to a decrease in the lateral size of the self-assembled islands and an increase in their surface density. The decrease in the lateral size is associated both with the increase in the germanium content in the self-assembled islands and with the increase in the fraction of the surface occupied by these islands. The observed shift in the position of the photoluminescence peak toward the low-energy range is also explained by the increase in the germanium content in the islands with an increase in the deposition rate v(Ge). (C) 2005 Pleiades Publishing, Inc.