We report strong visible photoluminescence (PL) at room temperature from oxidized Si and Ge nanoballs, which are composed of a spherical crystalline core and a surface oxide layer. To explain the experimental results, a model is proposed in which excitons are confined to a spherical shell, an interfacial layer between the crystalline core and the surface oxide layer, and in which the exciton confinement enhances the PL intensity.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics