Hot-filament metal oxide deposition (HFMOD): a novel method for depositing thin films of metallic oxides

Abstract

O presente artigo descreve um novo método para a síntese de filmes finos de óxidos metálicos. Um filamento de metal, que pode ser aquecido por uma fonte de corrente alternada é instalado numa câmara de vácuo. Por meio de um fluxômetro de massa, oxigênio pode ser admitido no interior da câmara. Da reação entre o oxigênio e o metal do filamento aquecido, espécies de óxidos voláteis Me x O y , onde Me é o metal, são formadas, se condensando num substrato colocado próximo ao filamento, formando o filme. Foi observado que os filmes finos de W x O y e Mo x O y podem ser depositados de forma satisfatória por este novo método. Embora várias outras técnicas de análise tenham sido usadas para caracterizar os óxidos, esta nota enfatiza os resultados obtidos por espectroscopia de fotoelétrons de raio-X (XPS).This short report describes a novel method for the synthesis of metal oxide thin films. The experimental setup consists of a metal filament installed inside a vacuum chamber. The filament can be heated by an ac power supply while oxygen is admitted into the chamber using a mass flowmeter. From reactions between oxygen and the heated metal filament, volatile oxide species, Me x O y , where Me is the metal, can be formed, condensing on a nearby substrate. We have observed that thin films of W x O y and Mo x O y can be satisfactorily deposited by this novel method. Although several techniques were used to characterize the oxides, this note emphasizes the results obtained by X-ray Photoelectron Spectroscopy (XPS).

Silicon based solar cells using a multilayer oxide as emitter

“…Obviously, the 4f profile can be fit by two Gaussian peaks centered at 37.9 and 35.8 eV, which are corresponding to the W 4f 5/2 and W 4f 7/2 orbital of tungsten in the W +6 valence state. 30 Similar spectra is revealed in Fig. 1(d), indicating that both WO 3 layers are stoichiometric WO 3 , in contrary to sub-stoichiometric WO x evaporated in vacuum.…”

Synthesis of ZrMo2O8 polymorphs by a melt quenching method and mechanochemical activation

“…Mo3d spectra are fitted to two doublets, with energies for Mo3d 5/2 at ∼233 eV -(the Higher Binding Energy component) HBE in Table 1 and at ∼232 eV -(the Lower Binding Energy component) LBE in Table 1. The 233 eV value can be assigned to the Mo (6+) oxidation state and that at 232 eV, to Mo (5+) [52][53][54]. The value of the binding energy (233.0 eV for Mo3d 5/2 ) of pure MoO 3 is in good agreement with the literature data [52,53].…”

Annealing effects on the structural and optical properties of vanadium oxide film obtained by the hot-filament metal oxide deposition technique (HFMOD)

“…Films are formed by the HFMOD process from VO x gaseous species generated at the filament surface due to thermal reactions between vanadium and oxygen. Description and details of the HFMOD technique are found in literature [7]. The filament temperature, measured during the deposition by an optical pyrometer through a quartz viewport in the chamber wall, ranged from 1365 to 1385 ºC.…”

“…The HFMOD is a very simple and inexpensive technique to deposit metal oxide films by heating metal wires of high fusion temperatures, as the transitions metals, in oxygen atmosphere [7]. Thin films of W [8,9,10], Mo [11,12] and V [10] oxides have been produced by this technique, where the electrochromic effect was observed for the W and Mo oxide films [10,12].…”