Optical absorption and interband transitions of AgSbTe2 films

The optical properties of AgSbTe2 thin films of different thicknesses were studied. Transmittance and reflectance measurements were used to calculate the energy gap width, the width of localized states, and the optical constants n and k. We came to the conclusion that the energy gap width decreases as film thickness increases, while the width of the tail of the localized state increases. We also found that, as the wavelength increases, the value of the refractive index remains nearly constant lambda > 600 nm, while the absorption index decreases.