In this work, the optical and electrical properties of carbon–nickel films annealed at different temperatures (300–1000 °C) were investigated. The obtained data of the refractive index n using the Swanepoel’s method can be analyzed to obtain the high-frequency dielectric constant which describes the free carriers and the lattice vibration modes of dispersion. The lattice dielectric constant εL and the plasma frequency ωp at 500 °C have maximum values 4.95 and 40.02×106 Hz, respectively. The free carrier electric susceptibility measurements in wavelength range (300–1000 nm) are discussed according to the Spitzer–Fan model. It is shown that the electric susceptibility at 500 °C has maximum value and with increasing wavelength it increases. It is also shown that the waste of electrical energy as heat at 500 °C has maximum value and with increasing wavelength it increases. It is found that energy loss by the free charge carriers when traversing the bulk and surface of films at 800 °C has a minimum value and it is approximately constant with wavelength. It is shown that optical properties were consistent with electrical properties of films annealed at different temperatures in temperature range (15–500 K).
