Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1691862 | Vacuum | 2006 | 6 Pages |
The optical constants (absorption coefficient (α), refractive index (n), extinction coefficient (k), real and imaginary part of dielectric constant) have been studied for a-Se96−xTe4Agx (where x=0x=0, 4, 8, 12) thin films as a function of photon energy in the wavelength range (500–1000 nm). It has been found that the optical band gap increases while n and k decreases on incorporation of Ag in Se–Te system. The value of α and k increases, while the value of n decreases with incident photon energy. The results are interpreted in terms of the change in concentration of localized states due to the shift in fermi level. A correlation between the optical band gap and electronegativity of the alloys indicates that the optical band gap increases with the decrease of electronegativity.