Raman study of Si-Ge intermixing in Ge quantum rings and dots
Journal
Physica E: Low-Dimensional Systems and Nanostructures
Journal Volume
28
Journal Issue
4
Pages
531-536
Date Issued
2005
Author(s)
Abstract
The Ge/Si (1 0 0) nanostructures have been studied by atomic force microscopy (AFM) and Micro Raman optical spectroscopy. Two layers of Ge of total thickness 0.75 nm and Si cap with thickness 2.5 nm were deposited by the method of molecular beam epitaxy at the temperature range 640-700°C. AFM shows both quantum dots and ring-shape Ge nanostructures. From the analysis of the intensity and energy shift of the Raman signal we have found that the average concentration of Ge decreases considerably from 44% to 27%, when the growth temperature increases, whereas the degree of strain relaxation remains roughly the same. This allows us to conclude that intermixing is a dominating mechanism for strain relaxation in processes of transformation of Ge quantum dots to quantum rings. © 2005 Elsevier B.V. All rights reserved.
Subjects
Germanium; Quantum dots; Quantum rings; Raman scattering
SDGs
Other Subjects
Atomic force microscopy; Germanium; Molecular beam epitaxy; Nanostructured materials; Optical properties; Raman scattering; Strain control; Thermal effects; Optical spectroscopy; Quantum rings; Raman signals; Strain relaxation; Semiconductor quantum dots
Type
journal article