Ellipsometric control of the parameters of lead selenide films during oxidation

The changes in the optical characteristics of lead selenide thin films with different degrees of oxidation are investigated using ellipsometry. It is found that, as the degree of oxidation increases, the refractive index, the optical thickness, and the extinction coefficient of lead selenide films decrease monotonically, whereas the effective film thickness increases. The composition of the films can be determined from the measured refractive index at a wavelength λ = 632.8 nm with the use of the dependences calculated on the basis of the single-layer model.