Optical Properties of Si and Ge/Si Nanocrystals in Silicon Oxide Matrix

Abstract

The contribution of oxide-related emission in Photoluminescence (PL) spectra from Ge and Si nanocrystals mixture embedded in silicon oxide (Ge/Si-SiO₂) and Si nanocrystals embedded in silicon oxide (Si-SiO₂) thin film prepared by RF-magnetron co-sputtering method is investigated. All as-deposited thin films were annealed for 1 hour in the temperature range from 300 to 1100 °C in an Ar atmosphere. The samples were evaluated by using PL, Energy dispersive spectroscopy (EDX), Raman scattering and X-ray photoelectron spectroscopy (XPS) measurements. All the measurements were performed at room temperature. The maximum PL intensity of Ge+Si-SiO₂ mixture thin film has increased more than the Si-SiO₂ thin film by approximately 10 times. From the results of Raman scattering and XPS measurements, it is consider that the oxygen defect centers in the host material SiO₂ increased by the diffusion of Ge. An increase in the PL intensity of Ge+Si-SiO₂ mixture thin film is systematically discussed.