Fabrication and Properties of an Asymmetric Waveguide Containing Nanoparticles

Abstract

A wavelength-tunable light-emitting source consisting of a multilayer asymmetric waveguide structure was designed, modeled, and fabricated on a silicon substrate. The structure has two layers: a silica cladding and a zirconia-Glymo (γ-glycidoxypropyltrimetoxysilane) sol–gel-based waveguide layer. CdS and CdSe/ZnS colloidal nanoparticles (NPs) used as light-emission sources were incorporated into the waveguide layer. These NPs are however unstable in a low-pH environment. A zirconia-Glymo sol–gel film using acetylacetone as the zirconium chelating agent was developed, thus eliminating the often used acetic acid from the sol–gel synthesis and preserving the NPs in the waveguide formation process. The acetylacetone chelating agent allowed for a high degree of cross-linking between the Zr and the Glymo as indicated by the Zr-O-Si absorption observed by infrared spectroscopy. The incorporation of the photoemissive CdSe/ZnS core/shell nanoparticles within the zirconia gel asymmetric slab waveguide was demonstrated as a means to create miniature multispectral light sources.