Optical properties of ternary ZnS x Se1−x polycrystalline thin films
- 90 Downloads
Ternary ZnSxSe1−x polycrystalline thin films were prepared by evaporation in vacuum of 10−5 Torr. The molecular fractionx varied in the region o≦x≦1. The optical constants (the refractive indexn, the absorption indexk, and the absorption coefficientα) were determined in the wavelength range 300–1600nm. A plot representingα2=f(hv) shows that the ZnSxSe1−x polycrystalline thin films of different compositions have two direct transitions corresponding to the energy gapsE andE+Δ. The variation in eitherE orE+Δ withx indicates that this system belongs to the amalgamation type. Such variation follows a quadratic equation. The bowing parameter was found to be 0.456 eV, roughly equal to the calculated value 0.60 eV using the empirical pseudopotential method based on the virtual-crystal approximation, in which the disorder effect has not been taken into account.
Unable to display preview. Download preview PDF.
- 1.A.I. Kitaigorodsky:Mixed Crystals, Springer Ser. SolidState Sci.33 (Springer, Berlin, Heidelberg, New York 1984)Google Scholar
- 2.A. Lempicki: Phys. Rev.113, 1204 (1959)Google Scholar
- 3.B. Segall, D.T.F. Marple:Phys. and Chem. of II–VI Compounds, ed. by M. Aven and J.S. Prener (North-Holland, Amsterdam 1967) pp. 319–381Google Scholar
- 4.S. Larach, R.E. Shrader, C.F. Stocker: Phys. Rev.108, 587 (1957)Google Scholar
- 5.A. Ebina, E. Fukunaga, T. Takahashi: Phys. Rev. B10, 2495 (1974)Google Scholar
- 6.K.E. Kirschfeld, N. Nelkowski, T.S. Wagner: Phys. Rev. Lett.29, 66 (1972)Google Scholar
- 7.A.A El-Shazly, M.A. Kenawy, M.M. El-Nahass, H.T. El-Shair, A.M. Ebrahim: Thin Solid Films (under consideration)Google Scholar
- 8.S. Tolansky:Multiple-Beam Interferometry of Surfaces and Films (Oxford University Press, London 1948) pp. 147–150Google Scholar
- 9.L.N. Hadley, D.M. Dennison: J. Opt. Soc. Am.37, 451 (1947)Google Scholar
- 10.R. Richardson: J. Phys. C4 L287 (1971);4, L339 1971);5, L27 (1972)Google Scholar