Controllable surface-plasmon resonance in engineered nanometer epitaxial silicide particles embedded in silicon

Epitaxial CoSi₂ particles in a single-crystal silicon matrix are grown by molecular-beam epitaxy using a technique that allows nanometer control over particle size in three dimensions. These composite layers exhibit resonant absorption predicted by effective-medium theory. Selection of the height and diameter of disklike particles through a choice of growth conditions allows tailoring of the depolarization factor and hence of the surface-plasmon resonance energy. Resonant absorption from 0.49 to 1.04 eV (2.5 to 1.2 {μ}m) is demonstrated and shown to agree well with values predicted by the Garnett theory using the bulk dielectric constants for CoSi₂ and Si.