Water adsorption on phosphorous-carbide thin films

• Autores: Broitman, E.; Furlan, A.; Gueorguiev, G.K.; Czigány, Zs.; Tarditi, Ana Maria; Gellman, Andrew J; Stafström, S.; Hultman, L.
• Año de publicación: 2009
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Phosphorous Carbide; Dangling Bonds; Water Adsorption; Density Functional Theory
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Amorphous phosphorous-carbide films have been considered as a new tribological coating material with unique electrical properties. However, such CPx films have not found practical use until now because they tend to oxidize/hydrolyze rapidly when in contact with air. Recently, we demonstrated that CPx thin films with a fullerene-like structure can be deposited by magnetron sputtering, whereby the structural incorporation of P atoms induces the formation of strongly bent and inter-linked graphene planes. Here, we compare the uptake of water in fullerene-like phosphorous-carbide (FL-CPx) thin films with that in amorphous phosphorous-carbide (a-CPx), and amorphous carbon (a-C) thin films. Films of each material were deposited on quartz crystal substrates by reactive DC magnetron sputtering to a thickness in the range 100-300 nm. The film microstructure was characterized by X-ray photoelectron spectroscopy, and high resolution transmission electron microscopy. A quartz crystal microbalance placed in a vacuum chamber was used to measure their water adsorption. Measurements indicate that FL-CPx films adsorbed less water than the a-CPx and a-C ones. To provide additional insight into the atomic structure of defects in the FL-CPx and a-CPx compounds, we performed first-principles calculations within the framework of density functional theory. Cohesive energy comparison reveals that the energy cost formation for dangling bonds in different configurations is considerably higher in FL-CPx than for the amorphous films. Thus, the modeling confirms the experimental results that dangling bonds are less likely in FL-CPx than in a-CPx and a-C films.
Fil: Broitman, E.. University of Carnegie Mellon; Estados Unidos
Fil: Furlan, A.. Linköping University; Suecia
Fil: Gueorguiev, G.K.. Linköping University; Suecia
Fil: Czigány, Zs.. Research Institute For Technical Physics And Materials Science Hungarian Academy Of Sciences;
Fil: Tarditi, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina
Fil: Gellman, Andrew J. University of Carnegie Mellon; Estados Unidos
Fil: Stafström, S.. Linköping University; Suecia
Fil: Hultman, L.. Linköping University; Suecia