Electrical and optical properties of Se1−xTex films

Thin films of Se-Te were fabricated by co-evaporating the separate elements in a vacuum. Careful control was exercised over the deposition rates in order to obtain a wide range in film composition, i.e. Se, Se_0.9Te_0.1, Se_0.8Te_0.2,… Se_0.1Te_0.9, Te. Reflectance, transmittance and absorptance measurements were made in the spectral range 0.4–2.5 μm and the values of the refractive index n and the extinction coefficient k were computed. The effect of increasing tellurium concentration in selenium films on the parameters n and k and on the absorption edge is discussed. The results for the electrical conductivity were also found to support those of the optical studies.