SYNTHESIS AND OPTICAL PROPERTIES OF DIFFICULT OXIDES FILMS BASED ON STANNUM AND NIOBIUM
Difficult oxide structure films Sn^Nb<sub>2</sub>O<sub>7</sub> onto monocrystal silicon and quartz substrates were synthesized. Samples were prepared by dc magnetron sputtering of niobium films, further thermal oxidation of obtained Nb/Si systems and modification of niobium oxide NbO<sub>2</sub> by stannum. The Sn-NbO<sub>2</sub> film systems obtained were annealed in a vacuum and a oxygen flux at a temperature of 773 K. Concentration distributions of components in a film was determined by the Reserford back scaterring (RBS) - method. The data of this method testify about of diffusion penetration of stannum into a niobium oxide film in the course of vacuum annealing. By the methods of scanning electron microscopy (SEM) and atomic force microscopy (AFM) is established, that increasing of the annealing temperature promote enlargement of crystallites at constantly smooth surface of a film with value of a roughness ~ 10 nm. The niobium oxide film by optical is more transparent, than the film obtained after annealing in a vacuum of the systems Sn-NbO<sub>2</sub>, and is less transparent, than a film of difficult oxide structure Sn<sub>2</sub>Nb<sub>2</sub>O<sub>7</sub>, received during the subsequent thermal oxidiation. Energy values of direct transitions were obtained. For a film NbO<sub>2</sub> this value is 4.02 eV and 4.19 eV for a film based on niobium oxide Nb<sub>2</sub>O<sub>5</sub> hexagonal modification and difficult oxide structure Sn^Nb<sub>2</sub>O<sub>7.</sub>