Effect of composition on optical properties of co-evaporated Mn/SiOx, Cr/SiOx and Cu/SiOx cermet thin films

• Published in: Journal of materials science 1995-12, Vol.30 (23), p.5867-5871
• Main Authors: ZAIDI, S. Z. A, BEYNON, J, WATERS, D. N, CHAUDHARY, A. J
• Format: Article
• Language: English
• Subjects: Composite materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optical properties of specific thin films; Physics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF01151499

Optical absorption spectra of amorphous Mn/SiOx, Cr/SiOx, and Cu /SiOx cermet films, 300 nm thick, with compositions from 0 to 25 at% Mn, Cr and Cu, respectively, prepared by co-evaporation at 293 K in vacuo were investigated. The linearity of (alpha h omega) exp(1/2) versus h omega graphs in the high absorption region for all the cermet films indicates that indirect photon transitions in k-space are involved in the absorption process. Tauc's rule is also confirmed. In all cases the optical energy gap decreases significantly with increasing metallic content of the films and the width of the tail of localised states increases. 36 refs.