TiO2 mesoporous thin film architecture as a tool to control Au nanoparticles growth and sensing capabilities

Low friction polytetrafluoroethylene (PTFE) has been studied extensively and is widely used in tribological applications in bulk form. Tribological properties of thin film PTFE are less reported due to its poor wear resistance. Here, we show that by incorporating Au nanoparticles in PTFE thin film, it is possible to significantly increase the wear resistance of the film. PTFE/Au nanoparticle composite thin films were fabricated on stainless steel substrates by dipping the substrate into a mixture of Au nanoparticle solution and PTFE aqueous dispersion. The friction and wear test results show that Au nanoparticles significantly reduced the wear of the PTFE thin film while preserving its low coefficient of friction (COF). Furthermore, substrate surface topography was found to have a significant effect on the friction and wear performances.

Download Full-text

Preparation of Highly Ordered Mesoporous Thin Film with Alkyltrimethylammonium(CnTMA+)

MRS Proceedings ◽

10.1557/proc-581-423 ◽

1999 ◽

Vol 581 ◽

Cited By ~ 2

Author(s):

Y. Goto ◽

N. Sugimoto ◽

Y Fukushima ◽

Y. Imada ◽

Y. Kubota ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Nitrogen Adsorption ◽

Steel Vessel ◽

Synthesis Conditions ◽

Ordered Mesoporous ◽

Mesoporous Thin Films ◽

Powder Samples ◽

Mesoporous Thin Film ◽

Nitrogen Adsorption Isotherms

ABSTRACTWe synthesized the highly ordered mesoporous thin films with alkyltrimethyl-ammonium (CnTMA+). The arrangement of mesopores was depend on the Si/surfactant ratio. The hexagonal(P6mm) arrangement was observed, when Surfactant/Si ratio was 1/10. Increasing the Surfactant/Si ratio to 1.6/10, the cubic (Pm3n) arrangements were observed. A steel vessel for the measurement of the nitrogen adsorption isotherms of thin film on the substrate was designed. It was found that mesopore arrangements in the film is more regular than that in the powder samples prepared by the same acidic synthesis conditions.

Download Full-text

Au Nanoparticles as Template for Defect Formation in Memristive SrTiO3 Thin Films

Nanomaterials ◽

10.3390/nano8110869 ◽

2018 ◽

Vol 8 (11) ◽

pp. 869 ◽

Cited By ~ 5

Author(s):

Nicolas Raab ◽

Dirk Schmidt ◽

Hongchu Du ◽

Maximilian Kruth ◽

Ulrich Simon ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Atomic Force Microscopy ◽

Au Nanoparticles ◽

Defect Formation ◽

Subsequent Growth ◽

Force Microscopy ◽

Atomic Force ◽

Oxygen Exchange Reaction ◽

Defect Nucleation

We investigated the possibility of tuning the local switching properties of memristive crystalline SrTiO 3 thin films by inserting nanoscale defect nucleation centers. For that purpose, we employed chemically-synthesized Au nanoparticles deposited on 0.5 wt%-Nb-doped SrTiO 3 single crystal substrates as a defect formation template for the subsequent growth of SrTiO 3 . We studied in detail the resulting microstructure and the local conducting and switching properties of the SrTiO 3 thin films. We revealed that the Au nanoparticles floated to the SrTiO 3 surface during growth, leaving behind a distorted thin film region in their vicinity. By employing conductive-tip atomic force microscopy, these distorted SrTiO 3 regions are identified as sites of preferential resistive switching. These findings can be attributed to the enhanced oxygen exchange reaction at the surface in these defective regions.

Download Full-text

Facile deposition and plasmonic resonance of Ag–Au nanoparticles in titania thin film

New Journal of Chemistry ◽

10.1039/c5nj00710k ◽

2015 ◽

Vol 39 (8) ◽

pp. 6522-6530 ◽

Cited By ~ 13

Author(s):

Mohan Chandra Mathpal ◽

Promod Kumar ◽

Anand Kumar Tripathi ◽

R. Balasubramaniyan ◽

Manish Kumar Singh ◽

...

Keyword(s):

Thin Film ◽

Au Nanoparticles ◽

Spray Coating ◽

Au Nanoparticle ◽

Plasmonic Resonance ◽

Titania Thin Film

A systematic diagram of fast and simple fabrication of Ag–Au nanoparticle based plasmonic thin film by spray coating.

Download Full-text

Effect of Ar Gas Pressure on LSPR Property of Au Nanoparticles: Comparison of Experimental and Theoretical Studies

Nanomaterials ◽

10.3390/nano10061071 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1071

Author(s):

Serap Yiğit Gezgin ◽

Abdullah Kepceoğlu ◽

Yasemin Gündoğdu ◽

Sidiki Zongo ◽

Anna Zawadzka ◽

...

Keyword(s):

Thin Films ◽

Near Infrared ◽

Au Nanoparticles ◽

Wavelength Region ◽

Gas Pressure ◽

Nano Particles ◽

Au Nanoparticle ◽

Localized Surface Plasmon ◽

Ambient Gas ◽

Ar Gas

In this study, the thin films were produced by using pulsed laser deposition (PLD) technique from gold (Au) nanoparticles deposited on two kinds of substrates under different argon (Ar) gas pressure. Microscope glass slides and silicon (100) wafers were used as amorphous and crystal substrates. The films were deposited under 2 × 10−3 mbar, 1 × 10−2 mbar, 2 × 10−2 mbar argon (Ar) ambient gas pressure. Effect of the background gas pressure on the plasma plume of the ablated Au nanoparticles was investigated in details. Morphology of Au nanoparticle thin films was investigated by means of atomic force microscopy (AFM) technique. Absorption spectra of Au nanoparticles were examined by using UV-Vis spectrometry. Extinction spectra of Au nanoparticles were calculated by using metallic nano particles boundary element method (MNPBEM) simulation programme. Both experimental spectra and simulation data for Au nanoparticles were obtained and compared in this work. It was concluded that they are also in good agreement with literature data. The measurements and the simulation results showed that localized surface plasmon resonance (LSPR) peaks for Au nanoparticles were located in the near infrared region (NIR) because of the larger size of the disk-like shape of Au nanoparticles, and the near-field coupling between Au nanoparticles. It was demonstrated that as the ambient gas (Ar) pressure was increased, the size and the density of Au nanoparticles on the substrate were decreased and the LSPR peak shifts toward the short wavelength region in the spectrum. This shift has been explained by the changes in the morphology of produced thin films.

Download Full-text

One step synthesis of Au nanoparticle-cyclized polyacrylonitrile composite films and their use in organic nano-floating gate memory applications

Journal of Materials Chemistry C ◽

10.1039/c5tc04166j ◽

2016 ◽

Vol 4 (7) ◽

pp. 1511-1516 ◽

Cited By ~ 7

Author(s):

Se-Phin Cho ◽

Sukjae Jang ◽

Hae-Na Jo ◽

Sang-A Lee ◽

Sukang Bae ◽

...

Keyword(s):

Thin Films ◽

Au Nanoparticles ◽

Solid Phase ◽

Composite Films ◽

Annealing Process ◽

Floating Gate ◽

Au Nanoparticle ◽

Floating Gate Memory ◽

One Step ◽

Memory Applications

In this study, we synthesized Au nanoparticles (AuNPs) in polyacrylonitrile (PAN) thin films using a simple annealing process in the solid phase.

Download Full-text

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069715 ◽

1970 ◽

Vol 28 ◽

pp. 544-545

Author(s):

R. C. Moretz ◽

G. G. Hausner ◽

D. F. Parsons

Keyword(s):

Thin Film ◽

Thin Films ◽

Electron Microscope ◽

Steady State ◽

Room Temperature ◽

Small Mass ◽

Equilibrium Pressure ◽

Biological Objects ◽

Mechanical Pump ◽

Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Download Full-text

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089652 ◽

1991 ◽

Vol 49 ◽

pp. 1068-1069

Author(s):

M. Grant Norton ◽

C. Barry Carter

Keyword(s):

Thin Film ◽

Thin Films ◽

Laser Ablation ◽

Substrate Surface ◽

Pulsed Laser ◽

Pulsed Laser Ablation ◽

Thin Film Deposition ◽

Film Deposition ◽

Laser Ablation Process ◽

Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

Download Full-text

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089718 ◽

1991 ◽

Vol 49 ◽

pp. 1080-1081

Author(s):

P. Lu ◽

W. Huang ◽

C.S. Chern ◽

Y.Q. Li ◽

J. Zhao ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Film Growth ◽

Chemical Vapor ◽

Microstructural Characterization ◽

Ion Milling ◽

Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

Download Full-text

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134922 ◽

1990 ◽

Vol 48 (2) ◽

pp. 264-265

Author(s):

D. R. Liu ◽

S. S. Shinozaki ◽

R. J. Baird

Keyword(s):

Thin Film ◽

Thin Films ◽

Monte Carlo Simulation ◽

Monte Carlo ◽

Compound Semiconductors ◽

Energy Dispersive Analysis ◽

X Ray ◽

Metastable Alloys ◽

Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

Download Full-text