Quantum confinement of quasi-two-dimensional E1 excitons in Ge nanocrystals studied by resonant Raman scattering

Abstract

Ge nanocrystals of diameters ranging from 4 to 10 nm were synthesized by ion implantation of Ge+ ions into SiO2 films followed by annealing. Confinement of its optical phonon and of the quasi-two-dimensional E1 exciton have been observed at room temperature by resonant Raman scattering. The observed size-dependent blueshifts of the E1 excitons energy (which can be larger than 0.7 eV) are found to be in good agreement with a theoretical calculation based on the effective mass approximation. ©2000 The American Physical Society.