Infrared Optical Constants of Chromium Nano-films

In the present work, nanofilms of chromium have been prepared by thermal evaporation in vacuum on to ultrasonically cleaned glass substrates held at room temperature (22 ^°C). Films have been characterized by using X-ray diffraction (XRD) spectra, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Infra-Red (IR) spectra were used to examine the morphology and nano-structures to find out the cause. The transmission measurements were made on chromium films in the thickness range (6 – 60) nm for the incident photon energy of wavelength range, (2.5 - 4.5) μm. The optical transmittances of films have been found to decrease with increase in the film thickness in the entire IR spectral region of incident photon energy. In this case the optical constants like refractive index (n), absorption coefficient (a), extinction coefficient (k), real part (ε′) and imaginary part (ε″) of relative permittivity are obtained from IR spectrum. (paper)