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Characterization of spray deposited bismuth oxide thin films and their thermal conversion to bismuth silicate

2004; Elsevier BV; Volume: 478; Issue: 1-2 Linguagem: Inglês

10.1016/j.tsf.2004.10.013

1879-2731

O. Rico-Fuentes, E. Sánchez-Aguilera, Celso Velásquez, R. Ortega-Alvarado, J. C. Alonso, A. Ortíz,

Photorefractive and Nonlinear Optics

Bismuth oxide films deposited by spray pyrolysis, using bismuth acetate or bismuth chloride, onto clear fused quartz and single-crystalline silicon substrates were thermally converted into bismuth silicate compounds. Bismuth silicate compounds' chemical compositions depend on the annealing temperature; Bi2SiO5 is obtained at 600 °C and Bi4Si3O12 is produced at 750 °C. Forbidden energy optical band gap increases from 3.78 eV for as-deposited films up to 4.89 eV for annealed films. Current densities of 10−6 A/cm2, in metal-insulator-semiconductor (MIS) structures, are observed for Bi2SiO5 films at applied electric fields 300 kV/cm and for Bi4Si3O12 films for 2.5 MV/cm. A value of the order of 10.6 was calculated for the apparent dielectric constant of the specimen obtained by annealing at 800 °C.