Raman scattering from three-dimensionally regimented quantum dot superlattices

2019-07-13 07:25:27

quantum Raman semiconductor phonon dot

责任者: Lazarenkova, Olga L.;Balandin, Alexander A. 单位: Nano-Device Laboratory, Department of Electrical Engineering, University of California-Riverside, Riverside, CA 92521, United States 来源出处: Superlattices and Microstructures,2003,33(1-2):95-101 摘要: We examine the low-energy part of Raman scattering spectrum from a three-dimensional regimented array of GexSi1-x quantum dots on Si. Our analysis is based on a numerical solution of the elasticity equation for the whole quantum dot superlattice. Three-dimensional acoustic phonon folding due to structure regimentation and small feature size leads to unique signatures in Raman spectra, which cannot be predicted using the Lamb-type models for quantum dots or the Rytov model for a quantum well superlattice. We found that symmetry breaking, which is achieved when the inter-dot distances are comparable to the dot dimensions, results in increased intensity of confined phonon modes. It is also shown that changes in dot material composition and alteration of the dot size lead to different Raman spectrum modification. The latter can be used as a tool to distinguish phonon confinement effects on Raman spectra from alloying and strain induced effects. 关键词: Semiconductor superlattices;Semiconductor quantum dots;Raman scattering;Semiconducting germanium compounds;Elasticity;Molecular structure;Composition;Nanostructured materials;Phonons;Semiconductor quantum wells;Alloying;Strain rate;Quantum dot superlattices;Acoustic phonon folding;Lamb type models;Strain induced effects;Confined phonons