Navegando por Palavras-chave "thin films"

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    Feasibility of RF Sputtering and PIIID for production of thin films from red mud
    (ABM, ABC, ABPol, 2014-10-01) Antunes, Maria Lúcia Pereira; Cruz, Nilson Cristino Da; Delgado, Adriana De Oliveira; Durrant, Steven Frederick; Bortoleto, José Roberto Ribeiro; Lima, Vivian Faria; Santana, Pericles Lopes; Caseli, Luciano [UNIFESP]; Rangel, Elidiane Cipriano; Universidade Estadual Paulista (UNESP); Universidade Federal de São Carlos; Universidade Federal de São Paulo (UNIFESP)
    During the extraction of aluminum from bauxite, a waste of oxides containing traces of heavy metals in a highly alkaline matrix, called Red Mud (RM), is produced. In this study RM is characterized and the feasibility of using it as a precursor for the production of thin films by Plasma Sputtering and by Plasma Immersion Ion Implantation and Deposition (PIIID) is demonstrated. The chemical structure and composition, surface morphology, topography, and wettability of the films prepared using such methodologies were investigated. The films consist mainly of the elements aluminum, silicon, iron and carbon. Infrared spectroscopic analyses reveal the presence of C=O, C-H2, Fe(OH), Al-O and Si-C functionalities. RF Sputtering produced films with smoother surfaces, whereas PIIID produced granular surface structures. Surface contact angle measurements showed that despite the presence of oxides and hydroxides, the films are hydrophobic, thus exhibiting an interesting link between the physical and thermodynamical properties.
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    The influence of aluminum incorporation on the Structural and Electrical Properties of ZnO Thin Films For Applications in Piezoresistive Sensors
    (IEEE, 2017) Cardoso, G. W. A. [UNIFESP]; Leal, G. [UNIFESP]; Massi, M. [UNIFESP]; da Silva Sobrinho, A. S.; Libardi, J.
    Zinc oxide thin films have high resistivity, plus thermal and chemical stability. Such properties make this material suitable for fabrication of piezo-electric sensors and surface acoustic wave devices that are used in Microelectromechanical systems (MEMS). The addition of metallic nanoparticles into the film matrix can reduce the value of resistivity, and, thus, qualify the material to be used in piezoresistive devices. In this work, a dc magnetron co-sputtering was used to grow Al doped ZnO (AZO) films with different applied voltages in the Al target, deposited on Si (100) p-type substrates with a layer of 1 micron of SiO2 by thermal oxidation. The microstructure and chemical composition of the films were characterized by X-ray diffraction and Rutterford-Backscattering techniques, respectively. The RBS results indicate the presence of aluminum, zinc, and oxygen in the films, which was confirmed by the XRD peaks of ZnO (002) at 2 theta=34.4 degrees Four probe technique confirmed a gradual reduction of resistivity up to 8.10(-3)Omega.cm as the applied power on the Al-target increased.