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SiO2 Substrates (sio2 + substrate)
Selected AbstractsSimple Patterning via Adhesion between a Buffered-Oxide Etchant-Treated PDMS Stamp and a SiO2 Substrate,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2007Y.-K. Kim Abstract A very simple polydimethylsiloxane (PDMS) pattern-transfer method is devised, called buffered-oxide etchant (BOE) printing. The mechanism of pattern transfer is investigated, by considering the strong adhesion between the BOE-treated PDMS and the SiO2 substrate. PDMS patterns from a few micrometers to sub-micrometer size are transferred to the SiO2 substrate by just pressing a stamp that has been immersed in BOE solution for a few minutes. The patterned PDMS layers work as perfect physical and chemical passivation layers in the fabrication of metal electrodes and V2O5 nanowire channels, respectively. Interestingly, a second stamping of the BOE-treated PDMS on the SiO2 substrate pre-patterned with metal as well as PDMS results in a selective transfer of the PDMS patterns only to the bare SiO2. In this way, the fabrication of a device structure consisting of two Au electrodes and V2O5 nanowire network channels is possible; non-ohmic semiconducting I,V characteristics, which can be modeled by serially connected percolation, are observed. [source] Optical, morphological and spectro- scopic characterization of graphene on SiO2PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010F. Giannazzo Abstract This work addresses the issue of determining the number of layers in few layers of graphene (FLG) flakes by cross-comparison of several techniques: optical microscopy (OM), atomic force microscopy (AFM) and micro-Raman (,R) spectroscopy. SL were preliminarily identified by ,R spectroscopy, which allows an unambiguous distinction between monolayers, bilayers and multilayers from the shape and relative intensity of the G and 2D peaks. It is demonstrated that the thickness of a SL measured by tapping mode AFM with respect to the SiO2 substrate is affected by an "offset" ,0.3 nm. This offset is explained in terms of the different adhesion forces between tip and SiO2 and tip and graphene measured by force spectroscopy curves. A calibration curve relating the height of a flake measured by AFM with the number of graphene layer was obtained. Finally, the optical contrast (OC) variations with FLG thickness was measured for different wavelengths in the visible range and for different oxide thicknesses (from 100 to 300 nm). OC was correlated with the number of layers (independently measured by AFM). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Formation of Metal Nano- and Micropatterns on Self-Assembled Monolayers by Pulsed Laser Deposition Through Nanostencils and Electroless Deposition,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2006A. Speets Abstract Patterns of noble-metal structures on top of self-assembled monolayers (SAMs) on Au and SiO2 substrates have been prepared following two approaches. The first approach consists of pulsed laser deposition (PLD) of Pt, Pd, Au, or Cu through nano- and microstencils. In the second approach, noble-metal cluster patterns deposited through nano- and microstencils are used as catalysts for selective electroless deposition (ELD) of Cu. Cu structures are grown on SAMs on both Au and SiO2 substrates and are subsequently analyzed using X-ray photoelectron spectroscopy element mapping, atomic force microscopy, and optical microscopy. The combination of PLD through stencils on SAMs followed by ELD is a new method for the creation of (sub)-micrometer-sized metal structures on top of SAMs. This method minimizes the gas-phase deposition step, which is often responsible for damage to, or electrical shorts through, the SAM. [source] Silicon Carbide Films by Laser Pyrolysis of PolycarbosilaneJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2001Paolo Colombo Thin films of polycarbosilane were deposited on Si and SiO2 substrates. Instead of conventional oven annealing (high temperatures, inert atmosphere), laser pyrolysis was used to achieve the polymer-to-ceramic conversion. In some conditions, especially when laser radiation absorption was enhanced by depositing a carbon layer on the surface of as-deposited films or by embedding graphite particles, this processing method yielded SiC ceramic coatings, without damaging the substrate. Processing in air or low vacuum did not result in oxidized coatings, contrary to what happens for oven pyrolysis. Laser-converted films were similar to oven-heated films processed at 1000° to 1200°C. [source] Preparation of ZnO thin film by the sol,gel method using low temperature ozone oxidationPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010Takashi Ehara Abstract Zinc oxide thin films have been prepared by the sol,gel method from a 2-methoxyethanol solution of zinc acetate dihydrate on SiO2 substrates using air, pure oxygen, and 1% ozone in oxygen as oxygen source. In the cases where air or oxygen was used as the oxygen source for thermal annealing, samples annealed at 600 to 800,°C exhibit a (0002) peak in X-ray diffraction (XRD). A sample annealed at 700,°C exhibited the highest (0002) peak intensity in conventional thermal annealing. However, the case using 1% ozone in oxygen as the atmosphere presented different results. A sample treated in 1% ozone at 100,°C had peak intensity in XRD (0002) comparable with samples annealed at several hundreds of degree in air or oxygen. This result indicates that the high oxidation efficiency of ozone is useful in decreasing the processing temperature of the sol,gel method. [source] IR-VIS-UV ellipsometry, XRD and AES investigation of In/Cu and In/Pd thin filmsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2008A. A. Wronkowska Abstract Optical and compositional properties of In, In/Pd and Pd/In/Pd thin films evaporated on Cu and SiO2 substrates in vacuum were investigated by means of X-ray diffractometry, Auger electron spectroscopy and spectroscopic ellipsometry methods. Auger depth profile studies were performed in order to determine the composition of InCu and InPd structures. In both systems interdiffusion of metals was detected at room temperature. The XRD patterns indicated formation of CuIn2 and PdIn3 phases in the samples. Optical properties of the composite layers containing intermetallic phases were derived from ellipsometric quantities , and , measured in the photon energy range 0.1-6.0 eV at different angles of incidence using suitable multilayer models for the examined samples. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||