Optical properties of epitaxial CoSi2 and NiSi2 films on silicon

Abstract
We have measured the optical constants of epitaxial films of CoSi2 and NiSi2, grown by molecular beam epitaxy on Si(111), in the energy range of 0.9–4.0 eV. The behavior of the optical constants is characteristic of metals: Drudelike in the low energy region and deviating from Drude behavior as interband transitions set in. Interband transitions are found to have already set in at 1 eV. The absorption varies significantly with energy, which has implications for photoresponse studies of internal photoemission in these material systems.