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Sample records for pt films deposited

  1. Perpendicular coercivity enhancement of CoPt/TiN films by nitrogen incorporation during deposition

    Science.gov (United States)

    An, Hongyu; Wang, Jian; Szivos, Janos; Harumoto, Takashi; Sannomiya, Takumi; Muraishi, Shinji; Safran, Gyorgy; Nakamura, Yoshio; Shi, Ji

    2015-11-01

    The effect of N incorporation on the structure and magnetic properties of CoPt thin films deposited on glass substrates with TiN seed layers has been investigated. During the deposition of CoPt, introducing 20% N2 into Ar atmosphere promotes the (001) texture and enhances the perpendicular coercivity of CoPt film compared with the film deposited in pure Ar and post-annealed under the same conditions. From the in situ x-ray diffraction results, it is confirmed that N incorporation expands the lattice parameter of CoPt, which favors the epitaxial growth of CoPt on TiN. During the post-annealing process, N releases from CoPt film and promotes the L10 ordering transformation of CoPt.

  2. Perpendicular coercivity enhancement of CoPt/TiN films by nitrogen incorporation during deposition

    Energy Technology Data Exchange (ETDEWEB)

    An, Hongyu; Harumoto, Takashi; Sannomiya, Takumi; Muraishi, Shinji; Nakamura, Yoshio; Shi, Ji, E-mail: Shi.j.aa@m.titech.ac.jp [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Wang, Jian [National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Szivos, Janos; Safran, Gyorgy [Hungarian Academy of Sciences, Research Institute for Technical Physics and Materials Science, H-1121 Budapest, Konkoly-Thege ut 29-33 (Hungary)

    2015-11-28

    The effect of N incorporation on the structure and magnetic properties of CoPt thin films deposited on glass substrates with TiN seed layers has been investigated. During the deposition of CoPt, introducing 20% N{sub 2} into Ar atmosphere promotes the (001) texture and enhances the perpendicular coercivity of CoPt film compared with the film deposited in pure Ar and post-annealed under the same conditions. From the in situ x-ray diffraction results, it is confirmed that N incorporation expands the lattice parameter of CoPt, which favors the epitaxial growth of CoPt on TiN. During the post-annealing process, N releases from CoPt film and promotes the L1{sub 0} ordering transformation of CoPt.

  3. Designed nanostructured pt film for electrocatalytic activities by underpotential deposition combined chemical replacement techniques.

    Science.gov (United States)

    Huang, Minghua; Jin, Yongdong; Jiang, Heqing; Sun, Xuping; Chen, Hongjun; Liu, Baifeng; Wang, Erkang; Dong, Shaojun

    2005-08-18

    Multiple-deposited Pt overlayer modified Pt nanoparticle (MD-Pt overlayer/PtNPs) films were deliberately constructed on glassy carbon electrodes through alternately multiple underpotential deposition (UPD) of Ag followed redox replacement reaction by Pt (II) cations. The linear and regular growth of the films characterized by cyclic voltammetry was observed. Atomic force spectroscopy (AFM) provides the surface morphology of the nanostructured Pt films. Rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry demonstrate that the MD-Pt overlayer/PtNPs films can catalyze an almost four-electron reduction of O(2) to H(2)O in air-saturated 0.1 M H(2)SO(4). Thus-prepared Pt films behave as novel nanostructured electrocatalysts for dioxygen reduction and hydrogen evolution reaction (HER) with enhanced electrocatalytic activities, in terms of both reduction peak potential and peak current, when compared to that of the bulk polycrystalline Pt electrode. Additionally, it is noted that after multiple replacement cycles, the electrocatalytic activities improved remarkably, although the increased amount of Pt is very low in comparison to that of pre-modified PtNPs due to the intrinsic feature of the UPD-redox replacement technique. In other words, the electrocatalytic activities could be improved markedly without using very much Pt by the technique of tailoring the catalytic surface. These features may provide an interesting way to produce Pt catalysts with a reliable catalytic performance as well as a reduction in cost.

  4. Optical properties of PMN-PT thin films prepared using pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tong, X.L., E-mail: tongxinglin@yahoo.com.cn [Key Laboratory of Fiber Optic Sensing Technology and Information Processing, Wuhan University of Technology, Ministry of Education, 122 Luoshi Road, Wuhan 430070 (China); Lin, K.; Lv, D.J.; Yang, M.H.; Liu, Z.X.; Zhang, D.S. [Key Laboratory of Fiber Optic Sensing Technology and Information Processing, Wuhan University of Technology, Ministry of Education, 122 Luoshi Road, Wuhan 430070 (China)

    2009-06-30

    (1 - x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} (PMN-PT) thin films have been deposited on quartz substrates using pulsed laser deposition (PLD). Crystalline microstructure of the deposited PMN-PT thin films has been investigated with X-ray diffraction (XRD). Optical transmission spectroscopy and Raman spectroscopy are used to characterize optical properties of the deposited PMN-PT thin films. The results show that the PMN-PT thin films of perovskite structure have been formed, and the crystalline and optical properties of the PMN-PT thin films can be improved as increasing the annealing temperature to 750 deg. C, but further increasing the annealing temperature to 950 deg. C may lead to a degradation of the crystallinity and the optical properties of the PMN-PT thin films. In addition, a weak second harmonic intensity (SHG) has been observed for the PMN-PT thin film formed at the optimum annealing temperature of 750 deg. C according to Maker fringe method. All these suggest that the annealing temperature has significant effect on the structural and optical properties of the PMN-PT thin films.

  5. Thermochemical hydrogen sensor based on Pt-coated nanofiber catalyst deposited on pyramidally textured thermoelectric film

    Science.gov (United States)

    Kim, Seil; Song, Yoseb; Lee, Young-In; Choa, Yong-Ho

    2017-09-01

    The hydrogen gas-sensing performance has been systemically investigated of a new type of thermochemical hydrogen (TCH) sensor, composed of pyramidally textured thermoelectric (TE) film and catalytic Pt-coated nanofibers (NFs) deposited over the TE film. The TE film was composed of stoichiometric Bi2Te3, synthesized by means of cost-effective electrochemical deposition onto a textured silicon wafer. The resulting pyramidally textured TE film played a critical role in maximizing hydrogen gas flow around the overlying Pt NFs, which were synthesized by means of electrospinning followed by sputtering and acted as a heating catalyst. The optimal temperature increase of the Pt NFs was determined by means of optimizations of the electrospinning and sputtering durations. The output voltage signal of the optimized TCH sensor based on Pt NFs was 17.5 times higher than that of a Pt thin film coated directly onto the pyramidal TE material by using the same sputtering duration, under the fixed conditions of 3 vol% H2 in air at room temperature. This observation can be explained by the increased surface area of (111) planes accessible on the Pt-coated NFs. The best response time and recovery time observed for the optimized TCH sensor based on Pt-coated NFs were respectively 17 and 2 s under the same conditions. We believe that this type of TCH sensor can be widely used for supersensitive hydrogen gas detection by employing small-size Pt NFs and various chalcogenide thin films with high thermoelectric performance.

  6. Plasma-assisted atomic layer deposition of conformal Pt films in high aspect ratio trenches

    Science.gov (United States)

    Erkens, I. J. M.; Verheijen, M. A.; Knoops, H. C. M.; Keuning, W.; Roozeboom, F.; Kessels, W. M. M.

    2017-02-01

    To date, conventional thermal atomic layer deposition (ALD) has been the method of choice to deposit high-quality Pt thin films grown typically from (MeCp)PtMe3 vapor and O2 gas at 300 °C. Plasma-assisted ALD of Pt using O2 plasma can offer several advantages over thermal ALD, such as faster nucleation and deposition at lower temperatures. In this work, it is demonstrated that plasma-assisted ALD at 300 °C also allows for the deposition of highly conformal Pt films in trenches with high aspect ratio ranging from 3 to 34. Scanning electron microscopy inspection revealed that the conformality of the deposited Pt films was 100% in trenches with aspect ratio (AR) up to 34. These results were corroborated by high-precision layer thickness measurements by transmission electron microscopy for trenches with an aspect ratio of 22. The role of the surface recombination of O-radicals and the contribution of thermal ALD reactions is discussed.

  7. Formation and Characterization of Pd, Pt and Pd-Pt Alloy Films on Polyimide by Catalyst-Enhanced Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jinlan; CHENG Yinhua; Yousuf Hamadan; YU Kaichao

    2007-01-01

    Platinum, palladium and their alloy films on polyimide were formed by catalyst-enhanced chemical vapor deposition (CVD) in the carrier gas (N2, O2) at 220-300 ℃ under reduced pressure and normal pressure. The deposition of palladium complexes [ Pd((η3-allyl)(hfac) and Pd(hfac)2 ] gives pure palladium film,while the deposition of platinum needs the enhancement of palladium complex by mixing precursor platinum complex Pt(COD)Me2 and palladium complex in the same chamber. The co-deposition of Pd and Pt metals was used for the deposition of alloy films. During the CVD of palladium-platinum alloy, the Pd/Pt atomic ratios vary under different co-deposition conditions. These metal films were characterized by XPS and SEM, and show a good adhesive property.

  8. Microstructures and magnetic properties of L1{sub 0} FePt films deposited on NaCl-type films

    Energy Technology Data Exchange (ETDEWEB)

    Sun, T.H., E-mail: s9931829@m99.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, S.C.; Su, W.H. [Department of Materials Engineering and Center for Thin Film Technologies and Applications, Ming Chi University of Technology, Taipei 24301, Taiwan (China); Chen, J.R. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2013-10-01

    A single-layered FePt film of 30 nm thickness with perpendicular magnetic anisotropy is achieved by depositing the film onto a heated Si(100) substrate at 620 °C. Its perpendicular coercivity (Hc{sub ⊥}), saturation magnetization (M{sub s}) and perpendicular squareness (S{sub ⊥}) are as high as 1113 kA/m, 0.594 Wb/m{sup 2} and 0.96, respectively. The perpendicular magnetic anisotropy degrades when a 5-nm NiO film is introduced under this single-layered film. Upon further increasing the thickness of the NiO film to 10 nm, the Hc{sub ⊥} of the single-layered film decreases greatly to around 330 kA/m. Compared to a NiO underlayer, the Hc{sub ⊥} of the FePt film remains above 1000 kA/m when a 10-nm MgO underlayer is introduced. Furthermore, when the thickness of the MgO underlayer is decreased to 5 nm, the perpendicular magnetic anisotropy of the single-layered FePt film is further enhanced. Its Hc{sub ⊥} stays high at 1081 kA/m; however, S{sub ⊥} increases significantly to 1. - Highlights: ► A thin MgO underlayer enhances the perpendicular magnetic anisotropy of FePt film. ► A NiO underlayer degrades the perpendicular magnetic anisotropy of the film. ► Ni atoms diffuse from NiO underlayer into FePt layer forming NiFe compounds.

  9. Magnetic properties of BaM /Pd-Pt double-layered thin film deposited at various substrate temperatures

    Science.gov (United States)

    Nahar Shams, Nazmun; Liu, Xiaoxi; Matsumoto, Mitsunori; Morisako, Akimitsu

    2005-05-01

    Crystallographic and magnetic properties of barium ferrite (BaM) thin films deposited onto Pt, Pd, and an alloy of Pd-Pt underlayers by sputtering at different substrate temperatures (Ts) from 400to600°C have been studied. It is found that the coercivity values in the perpendicular direction (Hcperp) of the BaM /Pd-Pt films are higher than those of the BaM films deposited on Pd and Pt underlayers. C-axis orientation of BaM /Pd-Pt film can be achieved at very low Ts of 450°C with a Hcperp of 2.1kOe for 30-nm BaM.

  10. Growth-induced magnetic anisotropy and clustering in vapor-deposited Co-Pt alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A.L.; Rooney, P.W.; Tran, M.Q.; Hellman, F. [Department of Physics, University of California--San Diego, La Jolla, California 92093 (United States); Ring, K.M.; Kavanagh, K.L. [Department of Electrical and Computer Engineering, University of California--San Diego, La Jolla, California 92093 (United States); Rellinghaus, B.; Weller, D. [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States)

    1999-11-01

    Polycrystalline and epitaxial (100)-, (110)-, and (111)-oriented CoPt{sub 3} and Co{sub 0.35}Pt{sub 0.65} films were deposited at various growth rates and over a range of growth temperatures from {minus}50 to 800&hthinsp;{degree}C. Films grown at moderate temperatures (200{endash}400&hthinsp;{degree}C) exhibit remarkable growth-induced properties: perpendicular magnetic anisotropy and large coercivity, as well as enhanced Curie temperature and low-temperature saturation magnetization. Magnetic measurements indicate significant Co clustering in these epitaxial fcc films. These properties are independent of crystallographic orientation, increase with increasing growth temperature, and vanish with annealing. We propose that the correlation between magnetic inhomogeneity, magnetic anisotropy, and enhanced moment is explained by clustering of Co into thin platelets in a Pt-rich lattice. This clustering occurs at the growth surface and is trapped into the growing film by low bulk atomic mobility. {copyright} {ital 1999} {ital The American Physical Society}

  11. STS study of TiO2 film and Pt-deposited TiO2 film in air

    Institute of Scientific and Technical Information of China (English)

    Zhang Min; Jin Zhensheng

    2004-01-01

    Direct investigation of the electronic structure of catalyst surfaces on the near-atomic scale in general has not been impossible in the past. However, with the advent of the scanning tunneling microscope (STM), the opportunity arises for incorporating the scanning tunneling spectroscopy (STS) for correlation in-situ surface electronic structure with topography on a sub-nanometer scale. In this paper, we report the STS results of thin film TiO2 and Pt-deposited TiO2 annealed at 450℃. It was found that the TiO2 semiconductor changes from n-type to p-type after Pt deposition.Fig. 1 shows the surface electronic property (Ⅰ-Ⅴ curve) of thin TiO2 film measured in air by STS. A steep descent of the anodic tunneling current at ca.- 1.0 Ⅴ and a rapid ascent of cathodic tunneling current at ca. +2.0V. The zero bias represents the Fermi level (Ef). Ef is situated at the Ecb side indicating that the thin TiO2 film possesses the same band gap as that of bulk TiO2 phase ( Egs =3.0 to 3.2 eV). For the sample of Pt-deposited TiO2 film, Pt/(Pt+Ti+O) atomic ratio≈0.2, which indicates that the surface of TiO2 film is partly covered by Pt particles, and there are two types of Ⅰ-Ⅴ curves to be detected. One of them (Fig.2a)is attributed to the electronic property of TiO2, which has same Egs as that shown in Fig. 1. However, the Ef is transferred to valence side (△≈1eV). This phenomenon hints that TiO2 is doped by an impurity which can introduce h+ into TiO2 lattice.Such a type of defects may be described by Ti1-xPtxO2(h )2x, here Pt+2 as a substitutional site of Ti+4. Fig.2b is the Ⅰ-Ⅴ curve of a Pt particle situated on a TiO2 particle contained Ti1-xPtxO2(h )2x.

  12. The structural transition from epitaxial Fe/Pt multilayers to an ordered FePt film using low energy ion beam sputtering deposition with no buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chih-Hao, E-mail: chlee@mx.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Yu-Sheng [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan (China); Liu, Li-Jung [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Huang, J.C.A. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-11-03

    An epitaxial L1{sub 0} FePt thin film grown from an [Fe(10 Å)/Pt(10 Å)]{sub 15} multilayer with the orientation of (001) was prepared by an ion beam sputtering deposition method without buffer layer. From the measurement data of X-ray diffraction and X-ray reflectivity, the multilayer structure was totally disappeared and a uniform FePt alloy thin film was formed at temperatures higher than 600 °C. For the as-deposited thin film grown at 100 °C, the multilayer already possesses an epitaxial structure. The epitaxial relation is FePt(001)[100]//MgO(001)[100] and this epitaxial relation persists after sequential high temperature annealing. An epitaxial L1{sub 0} ordered FePt(001) film with order parameter of 0.95 was obtained when the annealing temperature reached 650 °C. The ordered FePt(001) thin film has a perpendicular magnetic anisotropy with a squareness of 0.95 ± 0.03 on the magnetic hysteresis loop. This experiment demonstrates that the low energy ion beam sputtering deposition will preserve the epitaxial relation with no buffer layer between multilayer and substrate. - Highlights: • The Fe/Pt films using ion sputtering deposition with no buffer layer is epitaxial. • Multilayer structure was totally disappeared at temperatures higher than 600 °C. • Order parameter reach 0.95 after annealing at 650 °C. • Interfacial epitaxial FePt alloy already formed at 100 °C.

  13. Growth and microstructure of columnar Y-doped SrZrO{sub 3} films deposited on Pt-coated MgO by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Sijun, E-mail: sluo1@tulane.edu; Riggs, Brian C.; Shipman, Joshua T.; Adireddy, Shiva; Sklare, Samuel C.; Chrisey, Douglas B., E-mail: dchrisey@tulane.edu [Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118 (United States); Zhang, Xiaodong; Koplitz, Brent [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States)

    2015-07-21

    Direct integration of proton conductor films on Pt-coated substrates opens the way to film-based proton transport devices. Columnar SrZr{sub 0.95}Y{sub 0.05}O{sub 3−δ} (SZY) films with dense microstructure were deposited on Pt-coated MgO(100) substrates at 830 °C by pulsed laser deposition. The optimal window of ambient O{sub 2} pressure for good crystallinity of SZY films is from 400 to 600 mTorr. The ambient O{sub 2} compresses the plasma plume of SZY and increases the deposition rate. The 10 nm thick Ti adhesion layer on MgO(100) greatly affects the orientation of the sputtered Pt layers. Pt deposited directly on MgO shows a highly (111)-preferred orientation and leads to preferentially oriented SZY films while the addition of a Ti adhesion layer makes Pt show a less preferential orientation that leads to randomly oriented SZY films. The RMS surface roughness of preferentially oriented SZY films is larger than that of randomly oriented SZY films deposited under the same ambient O{sub 2} pressure. As the O{sub 2} pressure increased, the RMS surface roughness of preferentially oriented SZY films increased, reaching 45.7 nm (2.61% of film thickness) at 600 mTorr. This study revealed the ambient O{sub 2} pressure and orientation dependent surface roughness of SZY films grown on Pt-coated MgO substrates, which provides the potential to control the surface microstructure of SZY films for electrochemical applications in film-based hydrogen devices.

  14. Oxygen Reduction Reaction on Pt Overlayers Deposited onto a Gold Film: Ligand, Strain, and Ensemble Effect

    DEFF Research Database (Denmark)

    Deng, Yu-Jia; Tripkovic, Vladimir; Rossmeisl, Jan;

    2016-01-01

    We study the oxygen reduction reaction (ORR), the catalytic process occurring at the cathode in fuel cells, on Pt layers prepared by electrodeposition onto an Au substrate. Using a nominal Pt layer by layer deposition method previously proposed, imperfect layers of Pt on Au are obtained. The ORR ...

  15. A low-temperature synthesis of electrochemical active Pt nanoparticles and thin films by atomic layer deposition on Si(111) and glassy carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Han, Lihao [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Photovoltaic Materials and Devices (PVMD) Laboratory, Delft University of Technology, P.O. Box 5031, GA Delft 2600 (Netherlands); Huang, Zhuangqun; Ferrer, Ivonne M. [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Division of Chemistry and Chemical Engineering, California Institute of Technology, 210 Noyes Laboratory 127-72, Pasadena, CA 91125 (United States); Smets, Arno H.M.; Zeman, Miro [Photovoltaic Materials and Devices (PVMD) Laboratory, Delft University of Technology, P.O. Box 5031, GA Delft 2600 (Netherlands); Brunschwig, Bruce S., E-mail: bsb@caltech.edu [Beckman Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Lewis, Nathan S., E-mail: nslewis@caltech.edu [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Beckman Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Division of Chemistry and Chemical Engineering, California Institute of Technology, 210 Noyes Laboratory 127-72, Pasadena, CA 91125 (United States); Kavli Nanoscience Institute, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-07-01

    Atomic layer deposition (ALD) was used to deposit nanoparticles and thin films of Pt onto etched p-type Si(111) wafers and glassy carbon discs. Using precursors of MeCpPtMe{sub 3} and ozone and a temperature window of 200–300 °C, the growth rate was 80–110 pm/cycle. X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to analyze the composition, structure, morphology, and thickness of the ALD-grown Pt nanoparticle films. The catalytic activity of the ALD-grown Pt for the hydrogen evolution reaction was shown to be equivalent to that of e-beam evaporated Pt on glassy carbon electrode. - Highlights: • Pure Pt films were grown by atomic layer deposition (ALD) using MeCpPtMe3 and ozone. • ALD-grown Pt thin films had high growth rates of 110 pm/cycle. • ALD-grown Pt films were electrocatalytic for hydrogen evolution from water. • Electrocatalytic activity of the ALD Pt films was equivalent to e-beam deposited Pt. • No carbon species were detected in the ALD-grown Pt films.

  16. Structural and magnetic characterization of FePt films deposited onto SiO{sub 2} spherical particle arrays

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph; Makarov, Denys; Schatz, Guenter; Albrecht, Manfred [University of Konstanz, Department of Physics, D-78457 Konstanz (Germany); Maret, Mireille; Liscio, Fabiola [Laboratoire de Thermodynamique et Physico-Chimie Metallurgiques, ENSEEG, Saint Martin d' Heres (France)

    2007-07-01

    The growth of FePt films at 450 C on a Pt/Cr buffer layer deposited onto SiO{sub 2} spherical particle arrays and for comparison on flat thermally oxidized Si(001) substrates has been studied. The structural properties of the FePt films, such as the orientation and size of the crystalline grains and the degree of L1{sub 0}-type chemical ordering, were investigated by in-situ RHEED and ex-situ XRD. Magnetic characterization was performed by MFM, polar MOKE and SQUID. Increasing the Cr buffer underlayer thickness favors the formation of the FePt chemically ordered L1{sub 0} phase. An out-of-plane coercivity of the FePt alloy about 4 kOe was thus obtained for a Cr thickness of 50 nm. While the continuous films on oxidized Si(001) substrates show magnetic domain patterns with domain sizes in the range of 50-100 nm, multi-domain states are observed for the FePt alloy grown on the particle arrays. The influence of the Cr underlayer thickness and Pt buffer layer on the magnetic properties of FePt are discussed for various particle arrays and compared to micromagnetic simulations, providing a description of magnetization reversal.

  17. Influence of surface preparation on atomic layer deposition of Pt films

    Institute of Scientific and Technical Information of China (English)

    Ge Liang; Hu Cheng; Zhu Zhiwei; Zhang Wei; Wu Dongping; Zhang Shili

    2012-01-01

    We report Pt deposition on a Si substrate by means of atomic layer deposition (ALD) using (methylcyclopentadienyl) trimethylplatinum (CH3CsH4Pt(CH3)3) and O2.Silicon substrates with both HF-last and oxidelast surface treatments are employed to investigate the influence of surface preparation on Pt-ALD.A significantlylonger incubation time and less homogeneity are observed for Pt growth on the HF-last substrate compared to the oxide-last substrate.An interfacial oxide layer at the Pt-Si interface is found inevitable even with HF treatment of the Si substrate immediately prior to ALD processing.A plausible explanation to the observed difference of Pt-ALD is discussed.

  18. Deposition of thick Co-rich CoPtP films with high energy product for magnetic microelectromechanical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Santosh [Microsystems Center, Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland); Roy, Saibal, E-mail: saibal.roy@tyndall.i [Microsystems Center, Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2010-05-15

    We report the development of Co-rich CoPtP films of thicknesses up to 82 mum for use in magnetic MEMS applications. These films have been deposited using a combination of pulse-reverse plating with the addition of stress-relieving additives to the bath. The films were electroplated on sputtered Cu/Ti seed layer on silicon with an optimized thickness of 100/20 nm. The composition, crystalline structure, grain size and magnetic properties of the CoPtP films of varying thickness are compared and analyzed. The 3-mum-thick CoPtP film showed a columnar structure and strong perpendicular anisotropy. This film shows a perpendicular coercivity of 2150 Oe, a remanence of 0.564 T and a maximum energy product of 20 kJ/m{sup 3}. As the thickness of the plated film is increased, there is a gradual decrease in the coercivity and anisotropy. The 82-mum-thick film had a perpendicular coercivity of 1150 Oe and a remanence of 0.35 T. While there is a drop in coercivity and anisotropy, the remanence and maximum energy product remain constant for film thicknesses greater than 13 mum. The reason for the drop in coercivity and the near-constant remanence for thicker CoPtP films is discussed here. The coercivity of the thick Co-rich CoPtP film reported in this work is similar to those reported in the literature; the values of remanence, maximum energy product and saturation magnetization are the highest of all the thick (>50 mum) electroplated films in the literature.

  19. Unusually large magnetic anisotropy in electrochemically deposited Co-rich Co-Pt films.

    Science.gov (United States)

    Sirtori, V; Cavallotti, P L; Rognoni, R; Xu, X; Zangari, G; Fratesi, G; Trioni, M I; Bernasconi, M

    2011-06-01

    Co-rich Co-Pt films grown by electrodeposition from an amino-nitrite/citrate/glycine electrolyte onto Au(111) substrates apparently grow with a hexagonal structure, with its c-axis directed perpendicular to the surface. The films exhibit a perpendicular magnetic anisotropy (MCA) of the same order of magnitude as the shape anisotropy. Experimental estimates of the MCA result in a higher anisotropy than that reported for bulk materials of the same composition, but similar to values measured in films grown by vacuum methods at relatively high temperature, which partly consist of a high anisotropy, metastable orthorhombic Pmm2 phase. Comparison of valence band X-ray photoelectron spectroscopy measurements on electrodeposited films with density functional theory simulations of the electronic structure of the various reported Co(3)Pt structures support the notion that the films may consist of a mixture of the hexagonal and the Pmm2 structure.

  20. A curious interplay in the films of N-heterocyclic carbene PtII complexes upon deposition of alkali metals

    Science.gov (United States)

    Makarova, Anna A.; Grachova, Elena V.; Niedzialek, Dorota; Solomatina, Anastasia I.; Sonntag, Simon; Fedorov, Alexander V.; Vilkov, Oleg Yu.; Neudachina, Vera S.; Laubschat, Clemens; Tunik, Sergey P.; Vyalikh, Denis V.

    2016-05-01

    The recently synthesized series of PtII complexes containing cyclometallating (phenylpyridine or benzoquinoline) and N-heterocyclic carbene ligands possess intriguing structures, topologies, and light emitting properties. Here, we report curious physicochemical interactions between in situ PVD-grown films of a typical representative of the aforementioned PtII complex compounds and Li, Na, K and Cs atoms. Based on a combination of detailed core-level photoelectron spectroscopy and quantum-chemical calculations at the density functional theory level, we found that the deposition of alkali atoms onto the molecular film leads to unusual redistribution of electron density: essential modification of nitrogen sites, reduction of the coordination PtII centre to Pt0 and decrease of electron density on the bromine atoms. A possible explanation for this is formation of a supramolecular system “Pt complex-alkali metal ion” the latter is supported by restoration of the system to the initial state upon subsequent oxygen treatment. The discovered properties highlight a considerable potential of the PtII complexes for a variety of biomedical, sensing, chemical, and electronic applications.

  1. A curious interplay in the films of N-heterocyclic carbene Pt(II) complexes upon deposition of alkali metals.

    Science.gov (United States)

    Makarova, Anna A; Grachova, Elena V; Niedzialek, Dorota; Solomatina, Anastasia I; Sonntag, Simon; Fedorov, Alexander V; Vilkov, Oleg Yu; Neudachina, Vera S; Laubschat, Clemens; Tunik, Sergey P; Vyalikh, Denis V

    2016-05-06

    The recently synthesized series of Pt(II) complexes containing cyclometallating (phenylpyridine or benzoquinoline) and N-heterocyclic carbene ligands possess intriguing structures, topologies, and light emitting properties. Here, we report curious physicochemical interactions between in situ PVD-grown films of a typical representative of the aforementioned Pt(II) complex compounds and Li, Na, K and Cs atoms. Based on a combination of detailed core-level photoelectron spectroscopy and quantum-chemical calculations at the density functional theory level, we found that the deposition of alkali atoms onto the molecular film leads to unusual redistribution of electron density: essential modification of nitrogen sites, reduction of the coordination Pt(II) centre to Pt(0) and decrease of electron density on the bromine atoms. A possible explanation for this is formation of a supramolecular system "Pt complex-alkali metal ion"; the latter is supported by restoration of the system to the initial state upon subsequent oxygen treatment. The discovered properties highlight a considerable potential of the Pt(II) complexes for a variety of biomedical, sensing, chemical, and electronic applications.

  2. High perpendicular hard magnetic properties of nanocomposite Co-rich Co-Pt/Pt double-layered films by epitaxial deposition without capped layer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.C., E-mail: chensc@mail.mcut.edu.t [Department of Materials Engineering, MingChi University of Technology, Taipei 243, Taiwan (China); Kuo, P.C.; Shen, C.L.; Hsu, S.L.; Fang, Y.H.; Lin, G.P.; Huang, K.T. [Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China)

    2009-07-01

    The HRTEM cross-sectional lattice image shows that a well epitaxial growth of hcp Co-rich Co-Pt (002) on Pt (111) underlayer leads to good perpendicular magnetic anisotropy of Co-rich Co-Pt film. It is found that both the perpendicular coercivity (Hc{sub perpendicular}) and perpendicular squareness (S{sub perpendicular}) of Co-rich Co-Pt films without Pt capped layer are larger than that of Co-rich Co-Pt films with Pt capped layer. The cross-sectional TEM-EDS and AES analysis confirm that the oxygen atoms will diffuse from film surface into the Co-rich Co-Pt film without adding Pt capped layer, and it react with cobalt atoms to form CoO, which is detected by XPS analysis. The increase in perpendicular hard magnetic properties of Co-rich Co-Pt film without Pt capped layer is mainly due to form CoO in the Co-rich Co-Pt film.

  3. Photocatalytic Properties of TiO2 Thin Films Modified with Ag and Pt Nanoparticles Deposited by Gas Flow Sputtering.

    Science.gov (United States)

    Maicu, M; Glöss, D; Frach, Peter; Hecker, D; Gerlach, G; Córdoba, José M

    2015-09-01

    In this work, a gas flow sputtering (GFS) process which allows the production and deposition of metal nanoparticles (NPs) in a vacuum environment is described. Aim of the study is to prove the potential of this technology for the fabrication of new TiO2 films with enhanced photocatalytic properties. For this purpose, Ag and Pt NPs have been produced and deposited on photocatalytic float glass coated with TiO2 thin films by magnetron sputtering. The influence of the process parameters and of the metal amount on the final properties of the particles (quantity, size, size distribution, oxidation state etc.,) was widely investigated. Moreover, the effect of the NPs on the photocatalytic activity of the resulting materials was evaluated for the case of the decomposition of stearic acid (SA) during UV-A irradiation. The reduction of the water contact angle (WCA) during the irradiation period was measured in order to test the photo-induced super-hydrophilicity (PSH).

  4. Electrochemically induced sol-gel deposition of ZnO films on Pt-nanoparticle modified FTO surfaces for enhanced photoelectrocatalytic energy conversion.

    Science.gov (United States)

    Gutkowski, Ramona; Schuhmann, Wolfgang

    2016-04-28

    The low conductivity of transparent conductive oxides such as fluorine-doped tin oxides (FTO) has a high impact on the electrochemically induced deposition of semiconductor films for photoelectrocatalytic investigations. Furthermore, the often high recombination rate of photogenerated electron-hole pairs influences the photoelectrochemical performance of semiconductor films. In order to improve the semiconductor deposition process as well as to decrease electron-hole pair recombination, we propose modification of FTO by electrochemically induced deposition of Pt nanoparticles. The deposited Pt nanoparticles improve on the one hand the conductivity of the FTO and on the other hand they create nuclei at which the sol-gel semiconductor deposition starts. We use ZnO as a well-characterised material to evaluate the effect of the influencing parameters during electrochemically induced sol-gel deposition with respect to the incident photon-to-current efficiency (IPCE) derived from wavelength dependent photocurrent spectroscopy. Using optimised deposition parameters a substantially decreased recombination rate of photogenerated charge carriers is demonstrated, if Pt-nanoparticles are first deposited on the FTO surface. By improving the diffusion of photogenerated electrons to the Pt nanoparticles and hence to the back contact the photoelectrochemical performance of the deposited ZnO films is substantially increased.

  5. Surface-induced clustering in vapor deposited Co{sub 1{minus}x}Pt{sub x} and Ni{sub 1{minus}x}Pt{sub x} films (abstract)

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A.L.; Rooney, P.W.; Tran, M.Q.; Hellman, F. [Department of Physics, University of California--San Diego, La Jolla, California 92093-0350 (United States)

    1997-04-01

    We have depostied (100), (110), and (111) oriented single-crystal and polycrystalline Co{sub 1{minus}x}Pt{sub x} (x=0.65, 0.75, 0.80) and polycrystalline Ni{sub 1{minus}x}Pt{sub x} (x=0.25, 0.50) films over a range of growth temperatures from {minus}50 to 800{degree}C. Previous work on CoPt{sub 3} films had demonstrated the correlation between Co clustering and perpendicular magnetic anisotropy. These observations motivated a model in which Co atoms cluster on the growing surface; this clustering is trapped by succeeding layers for growth temperatures below 400{degree}C, the lower limit of bulk atomic mobility. The (110) oriented samples show clustering and anisotropy identical to the (100) and (11) oriented samples despite the sign change of the surface segregation in the (110) orientation. The Ni{endash}Pt alloy system is similar to Co{endash}Pt in structure, lattice constant, and the polarizability of Pt. We have deposited Ni{sub 3}Pt films; these films have significant clustering of the magnetic species which drops off rapidly after the onset of bulk mobility at 400{degree}C. No perpendicular magnetic anisotropy is found in these films, even though interface magnetic anisotropy values in Ni/Pt multilayers have been reported as having up to 1/4 the value of Co/Pt interfaces. Finally, in order to explore whether surface clustering is a kinetic or equilibrium effect, we have varied the deposition rate of CoPt{sub 3} over three orders of magnitude at temperatures below 400{degree}C. We found no dependence of clustering or anisotropy on the deposition rate, suggesting that the clustering is not kinetically limited but is a surface equilibrium effect. {copyright} {ital 1997 American Institute of Physics.}

  6. Tailoring out-of-plane magnetic properties of pulsed laser deposited FePt thin films by changing laser energy fluence

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying; Tan, T.L.; Tan, K.S.; Lee, P. [NSSE, NIE, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Liu, Hai; Yadian, Boluo; Hu, Ge; Huang, Yizhong; Ramanujan, R.V. [School of Material Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Rawat, R.S., E-mail: rajdeep.rawat@nie.edu.sg [NSSE, NIE, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore)

    2014-10-01

    Highlights: • Laser energy fluence (LEF) effect on composition, microstructure and magnetism. • Enhancing out-of-plane magnetic properties by tailoring LEF on target surface. • Higher LEF results in more energetic plasma species causing vacancy defects. • Formation of vacancy defect in FePt thin films leads to improved magnetic properties. • Best out-of-plane magnetic properties are achieved with medium LEF. - Abstract: Magnetic properties of pulsed laser deposited (PLD) FePt thin films are investigated at three different laser energy fluences of 51, 136 and 182 J/cm{sup 2}. Deposition at lower laser energy fluence (51 J/cm{sup 2}) yields softer out-of-plane coercivity (≤0.4 kG), whereas deposition at higher laser energy fluence (136 and 182 J/cm{sup 2}) results in harder out-of-plane coercivity (≥5.0 kG). The improved coercivity is found to be attributed to the formation of vacancy defects in thin films, which is indicated by stress change from tensile to compressive form with increasing laser energy fluence. Maximum out-of-plane saturated magnetization of 615 emu/cm{sup 3} and remanent squareness ratio of 0.88 are achieved for 16 nm thick FePt thin films deposited at moderate laser energy fluence of 136 J/cm{sup 2}, making them suitable for high density perpendicular data storage applications.

  7. Comparison of the microstructure and magnetic properties of strontium hexaferrite films deposited on Al2O3(0001), Si(100)/Pt(111) and Si(100) substrates by pulsed laser technique

    Science.gov (United States)

    Masoudpanah, S. M.; Seyyed Ebrahimi, S. A.; Ong, C. K.

    2014-01-01

    Strontium hexaferrite SrFe12O19 (SrM) films have been deposited on Al2O3(0001), Si(100)/Pt(111) and Si(100) substrates. The (001) oriented SrFe12O19 films deposited on the Al2O3(0001) and Si(100)/Pt(111) substrates have been confirmed by X-ray diffraction patterns. Higher coercivity in perpendicular direction rather than in-plane direction of the SrM/Al2O3(0001) and SrM/Pt(111) films showed that the films had perpendicular magnetic anisotropy. The (001) orientation and similar microstructure and magnetic properties of the SrM/Al2O3(0001) and SrM/Pt(111) films show the Al2O3(0001) substrate can be replaced by the Si(100)/Pt(111) substrate.

  8. Effects of Ag layers on the SiO2/FePt thin films deposited by magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    FAN Jiuping; XU Xiaohong; WANG Fang; JIANG Fengxian; TIAN Baoqiang; JIN Tao

    2008-01-01

    The effects of Ag Iayers with different locations and thicknesses on the structural and magnetic property of SiO2/FePt multilayer films were investigated.The non-magnetic Ag layer plays an important role in inducing(001)orientation and ordering of FePt grains,as well as the SiO2-doping reducing the grin size and the magnetic exchange coupling between grains.When the 10 nm Ag layer is moved from the bottom to the top of the SiO2/FePt multilayer film,the coercivity gradually decreases;the largest difference betwogn the out-of-plane coercivity and the in-plane one is obtained in the sample of[SiO2(2 nm)/FePt(3 nm)]3/Ag(10 nm)/[SiO2(2 nm)//FePt(3 nm)]2.Furthermore,the location of Ag layers was fixed and the thickness was changed.The XRD curves suggest that the intensity of the(001)peak becomes the strongest with the addition of 10 nm Ag layers.

  9. Understanding the Mechanism of Solvent-Mediated Adhesion of Vacuum Deposited Au and Pt Thin Films onto PMMA Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Alan K [ORNL; Brown, Victoria L. [James Madison University; Rugg, Brandon K. [James Madison University; Devore, Prof. Thomas C. [James Madison University; Meyer III, Harry M [ORNL; Hu, Dr. Xiaofeng [James Madison University; Hughes, Prof. W. Christopher [James Madison University; Augustine, Prof. Brian H. [James Madison University

    2012-01-01

    The adhesion of 100 nm thick electron-beam deposited Au and Pt and magnetron sputtered Au thin films onto poly(methyl methacrylate) (PMMA) substrates can be significantly enhanced to over 90% adhesion by either spin-casting or vapor-exposure to hydrohalocarbon solvents prior to metal deposition compared to samples that are either cleaned in isopropyl alcohol or pre-treated with a remote O2 plasma. X-ray photoelectron spectroscopy (XPS) and evolved gas Fourier transform infrared spectroscopy (EGA-FTIR) reveal the presence of residual halogenated solvent molecules at the PMMA surface which chemically activates the surface to produce a stable chemical interaction between the noble metal film and the PMMA. Density functional theory (DFT) calculations show that the halogenated solvent molecules preferentially form a Lewis acid-base adduct with the oxygen atoms in the ester group in PMMA which is consistent with the measured enthalpy of desorption of chloroform (CHCl3) on PMMA determined by EGA-FTIR to be 36 kJ mol-1. The DFT model also supports the experimentally observed change in the high resolution XPS O 1s peak at 533.77 eV after metallization attributed to a change in the local bonding environment of the bridging O in the PMMA ester group. DFT also predicts that the deposited metal atom (M) inserts into the C-X bond where X is the halogen atom on either CHCl3 or bromoform (CHBr3) to form a O M X interaction that is observed by a M-X bond in the high resolution XPS Cl 2p3/2 peak at 198.03 eV and Br 3p3/2 peak at 182.06 eV. A range of solvents with differing polarities for PMMA pre-treatment have been used and it is proposed that non-complexing solvents result in significant metal adhesion improvement. The Gutmann acceptor number can be used to predict the effectiveness of solvent treatment for noble metal adhesion. A model is proposed in which the bond energy of the C-X bond of the solvent must be sufficiently low so that the C-X bond can be cleaved to form the M

  10. Tailoring out-of-plane magnetic properties of pulsed laser deposited FePt thin films by changing laser energy fluence

    Science.gov (United States)

    Wang, Ying; Tan, T. L.; Tan, K. S.; Lee, P.; Liu, Hai; Yadian, Boluo; Hu, Ge; Huang, Yizhong; Ramanujan, R. V.; Rawat, R. S.

    2014-10-01

    Magnetic properties of pulsed laser deposited (PLD) FePt thin films are investigated at three different laser energy fluences of 51, 136 and 182 J/cm2. Deposition at lower laser energy fluence (51 J/cm2) yields softer out-of-plane coercivity (≤0.4 kG), whereas deposition at higher laser energy fluence (136 and 182 J/cm2) results in harder out-of-plane coercivity (≥5.0 kG). The improved coercivity is found to be attributed to the formation of vacancy defects in thin films, which is indicated by stress change from tensile to compressive form with increasing laser energy fluence. Maximum out-of-plane saturated magnetization of 615 emu/cm3 and remanent squareness ratio of 0.88 are achieved for 16 nm thick FePt thin films deposited at moderate laser energy fluence of 136 J/cm2, making them suitable for high density perpendicular data storage applications.

  11. Comparison of the microstructure and magnetic properties of strontium hexaferrite films deposited on Al{sub 2}O{sub 3}(0001), Si(100)/Pt(111) and Si(100) substrates by pulsed laser technique

    Energy Technology Data Exchange (ETDEWEB)

    Masoudpanah, S.M. [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); School of Materials Science and Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Seyyed Ebrahimi, S.A., E-mail: saseyyed@ut.ac.ir [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ong, C.K. [Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

    2014-01-15

    Strontium hexaferrite SrFe{sub 12}O{sub 19} (SrM) films have been deposited on Al{sub 2}O{sub 3}(0001), Si(100)/Pt(111) and Si(100) substrates. The (001) oriented SrFe{sub 12}O{sub 19} films deposited on the Al{sub 2}O{sub 3}(0001) and Si(100)/Pt(111) substrates have been confirmed by X-ray diffraction patterns. Higher coercivity in perpendicular direction rather than in-plane direction of the SrM/Al{sub 2}O{sub 3}(0001) and SrM/Pt(111) films showed that the films had perpendicular magnetic anisotropy. The (001) orientation and similar microstructure and magnetic properties of the SrM/Al{sub 2}O{sub 3}(0001) and SrM/Pt(111) films show the Al{sub 2}O{sub 3}(0001) substrate can be replaced by the Si(100)/Pt(111) substrate. - Highlights: • The SrFe{sub 12}O{sub 19} film deposited on different Si(100), Si(100)/Pt(111) and Al{sub 2}O{sub 3}(0001) substrates by PLD. • The SrM/Pt(111) and SrM/Al{sub 2}O{sub 3}(0001) films showed the c-axis perpendicular orientation. • The SrM/Al{sub 2}O{sub 3}(0001) films exhibited more perpendicular magnetic anisotropy than SrM/Pt(111) films. • The Al{sub 2}O{sub 3}(0001) substrate can be replaced by the Si(100)/Pt(111) substrate.

  12. Structural study of vapour phase deposited 3,4,9,10-perylene tetracarboxylicacid diimide: Comparison between single crystal and ultra thin films grown on Pt(100)

    Energy Technology Data Exchange (ETDEWEB)

    Guillermet, O. [Universite de la Mediterranee, Aix-Marseille II, CRMC-N, UPR CNRS 7251, Campus de Luminy, case 913, F-13288 Marseille Cedex 09 (France); Mossoyan-Deneux, M. [Universite de Provence, Aix-Marseille I, L2MP, UMR CNRS 6137, Faculte des Sciences de St Jerome, F-13397 Marseille Cedex 20 (France); Giorgi, M. [Service Commun de Cristallochimie, Universite Paul Cezanne, Aix-marseille III, Faculte des Sciences de St Jerome, F-13397 Marseille Cedex 20 (France); Glachant, A. [Universite de la Mediterranee, Aix-Marseille II, CRMC-N, UPR CNRS 7251, Campus de Luminy, case 913, F-13288 Marseille Cedex 09 (France)]. E-mail: glachant@crmcn.univ-mrs.fr; Mossoyan, J.C. [Universite de Provence, Aix-Marseille I, L2MP, UMR CNRS 6137, Faculte des Sciences de St Jerome, F-13397 Marseille Cedex 20 (France)

    2006-08-30

    Structural properties of a single crystal and of a thin film of 3,4,9,10-perylene-tetracarboxylic-acid-diimide are compared. The two samples are both obtained from the vapour phase, the latter being deposited at room temperature, in an ultrahigh vacuum environment, on a clean Pt(100) substrate. In the single crystal we have pointed out interactions between adjacent molecules by overlapping of the {pi} systems in the stacks and by hydrogen bonds between neighbouring stacks. The various surface unit cells of the nanocrystals from the film, identified by means of scanning tunnelling microscopy, are not comparable to those expected from the X-ray diffraction study of the single crystal and to those already published for other substrates. This fact clearly highlights the role played by the type of substrate chosen and/or the substrate-molecule interaction that affects the stacking and crystallinity of the growing crystal on top.

  13. Influence of piezoelectric strain on the Raman spectra of BiFeO{sub 3} films deposited on PMN-PT substrates

    Energy Technology Data Exchange (ETDEWEB)

    Himcinschi, Cameliu, E-mail: himcinsc@physik.tu-freiberg.de; Talkenberger, Andreas; Kortus, Jens [TU Bergakademie Freiberg, Institute of Theoretical Physics, 09596 Freiberg (Germany); Guo, Er-Jia [Institute of Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle (Germany); Institute for Metallic Materials, IFW Dresden, 01069 Dresden (Germany); Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Dörr, Kathrin [Institute of Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle (Germany); Institute for Metallic Materials, IFW Dresden, 01069 Dresden (Germany)

    2016-01-25

    BiFeO{sub 3} epitaxial thin films were deposited on piezoelectric 0.72Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.28PbTiO{sub 3} (PMN-PT) substrates with a conductive buffer layer (La{sub 0.7}Sr{sub 0.3}MnO{sub 3} or SrRuO{sub 3}) using pulsed laser deposition. The calibration of the strain values induced by the electric field applied on the piezoelectric PMN-PT substrates was realised using X-Ray diffraction measurements. The method of piezoelectrically induced strain allows one to directly obtain a quantitative correlation between the strain and the shift of the Raman-active phonons. This is a prerequisite for making Raman scattering a strong tool to probe the strain coupling in multiferroic nanostructures. Using the Poisson's number for BiFeO{sub 3}, one can determine the volume change induced by strain, and therefore the Grüneisen parameters for specific phonon modes.

  14. Influence of piezoelectric strain on the Raman spectra of BiFeO3 films deposited on PMN-PT substrates

    Science.gov (United States)

    Himcinschi, Cameliu; Guo, Er-Jia; Talkenberger, Andreas; Dörr, Kathrin; Kortus, Jens

    2016-01-01

    BiFeO3 epitaxial thin films were deposited on piezoelectric 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) substrates with a conductive buffer layer (La0.7Sr0.3MnO3 or SrRuO3) using pulsed laser deposition. The calibration of the strain values induced by the electric field applied on the piezoelectric PMN-PT substrates was realised using X-Ray diffraction measurements. The method of piezoelectrically induced strain allows one to directly obtain a quantitative correlation between the strain and the shift of the Raman-active phonons. This is a prerequisite for making Raman scattering a strong tool to probe the strain coupling in multiferroic nanostructures. Using the Poisson's number for BiFeO3, one can determine the volume change induced by strain, and therefore the Grüneisen parameters for specific phonon modes.

  15. Perpendicular magnetic anisotropy of Au/FePt thin films grown on Si substrates

    CERN Document Server

    Lee, Y W; Kim, C O

    1999-01-01

    FePt thin films show in plane magnetism with a very large coercive force when they are deposited on lattice-mismatched substrates, such as glass or Si In our research, FePt alloy thin films were deposited, using the coevaporation method, on a Au buffer layer which was evaporated onto a Si substrate at 500 .deg. C. The magnetic easy axis of the FePt film changed from the in-plane direction to the normal direction of the film. Therefore, it can be said that a Au buffer layer can enhance the perpendicular magnetic anisotropy of a FePt thin film on a lattice-mismatched substrate.

  16. PLD prepared nanostructured Pt-CeO2 thin films containing ionic platinum

    Science.gov (United States)

    Vorokhta, M.; Khalakhan, I.; Matolínová, I.; Nováková, J.; Haviar, S.; Lančok, J.; Novotný, M.; Yoshikawa, H.; Matolín, V.

    2017-02-01

    The composition of nanostructured Pt-CeO2 films on graphite substrates prepared by pulsed laser deposition has been investigated by means of hard X-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, and atomic force microscopy. The influence of morphology of the graphite substrates was investigated with respect to the relative concentrations of ionic and metallic Pt species in the films. It was found that the degree of Pt2+ enrichment is directly related to the surface morphology of graphite substrates. In particular, the deposition of Pt-CeO2 films on rough graphite substrate etched in oxygen plasma yielded nanostructured Pt-CeO2 catalyst films with high surface area and high Pt2+/Pt0 ratio. The presented results demonstrate that PLD is a suitable method for the preparation of thin Pt-CeO2 catalyst films for fuel cell applications.

  17. Improved dielectric properties of CaCu3Ti4O12 films with a CaTiO3 interlayer on Pt/TiO2/SiO2/Si substrates prepared by pulsed laser deposition

    Science.gov (United States)

    Lee, Sung-Yun; Kim, Hui Eun; Jo, William; Kim, Young-Hwan; Yoo, Sang-Im

    2015-11-01

    We report the greatly improved dielectric properties of CaCu3Ti4O12 (CCTO) films with a 60 nm-thick CaTiO3 (CTO) interlayer on Pt/TiO2/SiO2/Si substrates. Both CCTO films and CTO interlayers were prepared by pulsed laser deposition (PLD). With increasing the thickness of CCTO from 200 nm to 1.3 μm, the dielectric constants ( ɛ r ) at 10 kHz in both CCTO single-layered and CCTO/CTO double-layered films increased from ˜260 to ˜6000 and from ˜630 to ˜3700, respectively. Compared with CCTO single-layered films, CCTO/CTO double-layered films irrespective of CCTO film thickness exhibited a remarkable decrease in their dielectric losses ( tanδ) (Poole-Frenkel conduction model. [Figure not available: see fulltext.

  18. Biomimetic thin film deposition

    Science.gov (United States)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  19. Fabrication of monometallic (Co, Pd, Pt, Au) and bimetallic (Pt/Au, Au/Pt) thin films with hierarchical architectures as electrocatalysts

    Science.gov (United States)

    Qiu, Cuicui; Zhang, Jintao; Ma, Houyi

    2010-05-01

    Co thin films with novel hierarchical structures were controllably fabricated by simple electrochemical deposition in the absence of hard and soft templates, which were used as sacrificial templates to further prepare noble metal (Pd, Pt, Au) hierarchical micro/nanostructures via metal exchange reactions. SEM characterization demonstrated that the resulting noble metal thin films displayed hierarchical architectures. The as-prepared noble metal thin films could be directly used as the anode catalysts for the electro-oxidation of formic acid. Moreover, bimetallic catalysts (Pt/Au, Au/Pt) fabricated based on the monometallic Au, Pt micro/nanostructures exhibited the higher catalytic activity compared to the previous monometallic catalysts.

  20. Effect of Pt coverage in Pt-deposited Pd nanostructure electrodes on electrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ah-Reum; Lee, Young-Woo; Kwak, Da-Hee; Park, Kyung-Won [Soongsil University, Seoul (Korea, Republic of)

    2015-06-15

    We have fabricated Pt-deposited Pd electrodes via a two-gun sputtering deposition system by separately operating Pd and Pt target as a function of sputtering time of Pt target. For Pt-deposited Pd electrodes (Pd/Pt-X), Pd were first deposited on the substrates at 20 W for 5min, followed by depositing Pt on the Pd-only electrodes as a function of sputtering time (X=1, 3, 5, 7, and 10min) at 20W on the Pt target. As the sputtering time of Pt target increased, the portion of Pt on the Pd electrodes increased, representing an increased coverage of Pt on the Pd electrodes. The Pd/Pt-7 electrode having an optimized Pt coverage exhibits an excellent electrocatalytic activity for methanol oxidation reaction.

  1. Self-terminating growth of platinum films by electrochemical deposition.

    Science.gov (United States)

    Liu, Yihua; Gokcen, Dincer; Bertocci, Ugo; Moffat, Thomas P

    2012-12-07

    A self-terminating rapid electrodeposition process for controlled growth of platinum (Pt) monolayer films from a K(2)PtCl(4)-NaCl electrolyte has been developed that is tantamount to wet atomic layer deposition. Despite the deposition overpotential being in excess of 1 volt, Pt deposition was quenched at potentials just negative of proton reduction by an alteration of the double-layer structure induced by a saturated surface coverage of underpotential deposited H (H(upd)). The surface was reactivated for further Pt deposition by stepping the potential to more positive values, where H(upd) is oxidized and fresh sites for the adsorption of PtCl(4)(2-) become available. Periodic pulsing of the potential enables sequential deposition of two-dimensional Pt layers to fabricate films of desired thickness, relevant to a range of advanced technologies.

  2. IBA analysis and corrosion resistance of TiAlPtN/TiAlN/TiAl multilayer films deposited over a CoCrMo using magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Canto, C.E., E-mail: carloscanto2012@yahoo.com.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Andrade, E.; Lucio, O. de; Cruz, J.; Solís, C. [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Rocha, M.F. [ESIME-Z, IPN, U.P. ALM, Gustavo A. Madero, C.P. 07738 México D.F. (Mexico); Alemón, B. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Huegel, J.C. [Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico)

    2016-03-15

    The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.

  3. Electrodeposition of a Pt monolayer film: using kinetic limitations for atomic layer epitaxy.

    Science.gov (United States)

    Brimaud, Sylvain; Behm, R Jürgen

    2013-08-14

    A new and facile one-step method to prepare a smooth Pt monolayer film on a metallic substrate in the absence of underpotential deposition-type stabilizations is presented as a general approach and applied to the growth of Pt monolayer films on Au. The strongly modified electronic properties of these films were demonstrated by in situ IR spectroscopy at the electrified solid-liquid interface with adsorbed carbon monoxide serving as a probe molecule. The Pt monolayer on Au is kinetically stabilized by adsorbed CO, inhibiting further Pt deposition in higher layers.

  4. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  5. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  6. Nanoparticulate CoPt Thin Films

    Science.gov (United States)

    Barekatain, Yasaman; Hadjipanayis, George; Magnetics bLab Team

    Equiatomic FePt and CoPt alloys are very attractive for application in high density recording media because of the high magnetocrystalline anisotropy K of their fct(L10) structure with values exceeding 2MJ/m3.The aim of this study is to fabricate a nanoparticulate CoPt film consisting of CoPt nanoparticles embedded in a matrix. To obtain this we have used co-sputtering of CoPt with different materials M = BN,C, Cu and SiO2. Our first experiments were done on CoPt films with thickness of 200 nm. The as-sputtered films had the fcc structure and a coercivity of 150 Oe. Annealing at 700 oC for 30 min led to an increase in coercivity to 4 kOe. Optimization studies are under way to find the optimum sputtering conditions to obtain a fully ordered tetragonal structure with the highest value of coercivity which can then be used in the nanoparticulate composites. Work supported by DOE BES- FG02-04ERU4612 DOE DE-FG02-04ERU4612.

  7. Ordered iodine adsorption as fingerprint of (111) orientation of Pt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Braunschweig, Bjoern; Mitin, Alexej; Daum, Winfried [Institut fuer Physik und Physikalische Technologien, TU Clausthal, Leibnizstrasse 4, D-38678 Clausthal-Zellerfeld (Germany)

    2009-07-01

    Well-ordered Pt films deposited on re-usable substrates find applications such as inexpensive replacements for bulk single crystals or ultrathin transparent electrodes for spectro-electrochemical applications. While morphological properties of such films - roughness, atomic steps and spatial extent of atomically flat terraces - are easily imaged with the STM, atomic resolution of the Pt surface is often not attainable under environmental conditions. We demonstrate that the atomic surface structure of (111)-oriented Pt thin films deposited on {alpha}-Al{sub 2}O{sub 3}(0001) substrates is clearly revealed after adsorption of ordered iodine adlayers. In comparative STM studies with Pt thin films and with (111)-oriented bulk single crystals we observed the same coexisting (4 x 3{radical}(3)) and ({radical}(43) x {radical}(43)) iodine superstructures which indicates that our Pt films are highly ordered and (111)-oriented.

  8. Nanoscale study of the ferroelectric properties of SrBi{sub 2}Nb{sub 2}O{sub 9} thin films grown by pulsed laser deposition on epitaxial Pt electrodes using atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, Brice; Duclere, Jean-Rene; Guilloux-Viry, Maryline

    2003-07-15

    SrBi{sub 2}Nb{sub 2}O{sub 9} (SBN) thin films deposited by laser ablation on epitaxial (1 0 0)Pt and (1 1 0)Pt have been studied using an atomic force microscope (AFM) in the so-called 'piezoresponse' mode. Previous X-ray studies have shown that in the first case two different orientations coexist in the film: a predominant (0 0 1) orientation with a (1 1 5) orientation. AFM topographical images reveal the presence of two different kinds of grains of different shape corresponding to each orientation and AFM piezoresponse images are in agreement with the crystallographic orientation of the grains: only the expected (1 1 5) oriented grains show a piezoelectric contrast. Moreover, hysteresis loops are obtained over (1 1 5) grains and not over (0 0 1) regions. Although (1 1 5) grains can be in a monodomain state, they also show intragranular ferroelectric domains with nanometric sizes, which orientation can be reversed by applying a dc field between the AFM tip and the grounded conductive bottom electrode of the sample. In the second case, the use of a (1 1 0)Pt electrode instead of a (1 0 0)Pt electrode leads to preferentially (1 1 6) SBN oriented films, inducing far better ferroelectrics properties. In spite of a weak remnant polarization, the surface shows an homogeneous polarization when a 1 {mu}mx1 {mu}m area is probed after the reversal of the polarization by the AFM tip.

  9. Structural, ferroelectric and optical properties of Bi2VO5.5 thin films deposited on platinized silicon {(100) Pt/TiO2/SiO2/Si} substrates

    Science.gov (United States)

    Kumari, N.; Krupanidhi, S. B.; Varma, K. B. R.

    2008-06-01

    Bismuth vanadate (Bi2VO5.5, BVO) thin films have been deposited by a pulsed laser ablation technique on platinized silicon substrates. The surface morphology of the BVO thin films has been studied by atomic force microscopy (AFM). The optical properties of the BVO thin films were investigated using spectroscopic ellipsometric measurements in the 300 820 nm wavelength range. The refractive index (n), extinction coefficient (k) and thickness of the BVO thin films have been obtained by fitting the ellipsometric experimental data in a four-phase model (air/BVOrough/BVO/Pt). The values of the optical constants n and k that were determined through multilayer analysis at 600 nm were 2.31 and 0.056, respectively. For fitting the ellipsometric data and to interpret the optical constants, the unknown dielectric function of the BVO films was constructed using a Lorentz model. The roughness of the films was modeled in the Brugmann effective medium approximation and the results were compared with the AFM observations.

  10. Structural, ferroelectric and optical properties of Bi{sub 2}VO{sub 5.5} thin films deposited on platinized silicon (100) Pt/TiO{sub 2}/SiO{sub 2}/Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, N.; Krupanidhi, S.B.; Varma, K.B.R. [Indian Institute of Science, Materials Research Center, Bangalore (India)

    2008-06-15

    Bismuth vanadate (Bi{sub 2}VO{sub 5.5}, BVO) thin films have been deposited by a pulsed laser ablation technique on platinized silicon substrates. The surface morphology of the BVO thin films has been studied by atomic force microscopy (AFM). The optical properties of the BVO thin films were investigated using spectroscopic ellipsometric measurements in the 300-820 nm wavelength range. The refractive index (n), extinction coefficient (k) and thickness of the BVO thin films have been obtained by fitting the ellipsometric experimental data in a four-phase model (air/BVO{sub rough}/BVO/Pt). The values of the optical constants n and k that were determined through multilayer analysis at 600 nm were 2.31 and 0.056, respectively. For fitting the ellipsometric data and to interpret the optical constants, the unknown dielectric function of the BVO films was constructed using a Lorentz model. The roughness of the films was modeled in the Brugmann effective medium approximation and the results were compared with the AFM observations. (orig.)

  11. Palladium Electrodeposition onto Pt(100): Two-Layer Underpotential Deposition.

    Science.gov (United States)

    Previdello, Bruno A F; Sibert, Eric; Maret, Mireille; Soldo-Olivier, Yvonne

    2017-03-07

    Electrodeposition of the first Pd layers onto Pt(100) was investigated using cyclic voltammetry at a low scan rate (0.1 mV·s(-1)). Ultrathin films were characterized by cyclic voltammetry in 0.1 M H2SO4 solution and with ex situ AFM (atomic force microscopy). For the first time, we evidenced the underpotential character of the deposition of the first two Pd layers, characterized by a two-step mechanism, each step corresponding to the deposition of a complete Pd atomic layer. For thicker deposits, especially above 10 monolayers as equivalent thickness, the electrochemical characterization displays a strong irreversibility and a broadening of the adsorption/desorption peaks, associated with a reduction of long-range ordered flat areas. Ex situ AFM images are in agreement with this description. They show rough thick deposits and the growth of (100)-oriented rectangular shaped islands with their sides aligned with the two [011] and [0-11] perpendicular directions of the (100) Pt surface.

  12. Methanol electrooxidation on Pt particles dispersed into PANI/SWNT composite films

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Gang; Li, Li; Li, Jing-Hong; Xu, Bo-Qing [Innovative Catalysis Program, Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084 (China)

    2006-04-21

    Conducting polymer composite films comprised of polyaniline (PANI) and single wall carbon nanotubes (SWNT) was prepared by electrochemical codeposition during the electropolymerization in an aniline solution with suspending SWNT. The fabricated composite films are assessed with respect to their potential application as support materials in Pt electrocatalyst for electrochemical oxidation of methanol. The PANI/SWNT composite film incorporated with SWNT has a higher polymeric degree and lower defect density in PANI structure than PANI film. Furthermore, the incorporation of SWNT also leads to higher electrochemically accessible surface areas (S{sub a}), electronic conductivity and easier charge-transfer at polymer/electrolyte interfaces, which make higher dispersion and utilization for deposited Pt. Therefore, the Pt particles electrodeposited on PANI/SWNT composite polymer film exhibits excellent catalytic activity and stability for the electrooxidation of methanol in comparison to Pt supported on PANI film, which reveals that the composite film is more promising for application in electrocatalyst as a support material. (author)

  13. Effect of Cu additive on the structure and magnetic properties of (CoPt)1-xCux films

    Institute of Scientific and Technical Information of China (English)

    HUANG Tinging; WANG Fang; GUO Juhong; XU Xiaohong

    2009-01-01

    CoPt thin films with various Cu contents varying from 0 vol.% to 21.5 vol.% were deposited on glass substrates by magnetron sputtering. The effects of Cu additive on the structural and magnetic properties and the ordering temperature of CoPt films were investigated in detail. The results show that the Cu in CoPt films plays an important role in promoting the ordering parameter S and reducing the ordering tempera-ture of CoPt films. A nearly perfect (001) texture was obtained in a CoPt film doped with 15.3 vol.% Cu. Besides, the preferred orientation of the CoPt film can be changed by annealing temperature. The perpendicular growth of the CoPt film is favored at a high annealing tempera-ture.

  14. Interfacial oxygen migration and its effect on the magnetic anisotropy in Pt/Co/MgO/Pt films

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi; Feng, Chun, E-mail: fengchun@ustb.edu.cn, E-mail: ghyu@mater.ustb.edu.cn; Liu, Yang; Jiang, Shaolong; Hua Li, Ming; Hua Yu, Guang, E-mail: fengchun@ustb.edu.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Long Wu, Zheng [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China); Yang, Feng [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China)

    2014-02-03

    This paper reports the interfacial oxygen migration effect and its induced magnetic anisotropy evolution in Pt/Co/MgO/Pt films. During depositing the MgO layer, oxygen atoms from the MgO combine with the neighboring Co atoms, leading to the formation of CoO at the Co/MgO interface. Meanwhile, the films show in-plane magnetic anisotropy (IMA). After annealing, most of the oxygen atoms in CoO migrate back to the MgO layer, resulting in obvious improvement of Co/MgO interface and the enhancement of effective Co-O orbital hybridization. These favor the evolution of magnetic anisotropy from IMA to perpendicular magnetic anisotropy (PMA). The oxygen migration effect is achieved by the redox reaction at the Co/MgO interface. On the contrary, the transfer from IMA to PMA cannot be observed in Pt/Co/Pt films due to the lack of interfacial oxygen migration.

  15. The magnetic properties and microstructure of Co-Pt thin films using wet etching process.

    Science.gov (United States)

    Lee, Chang-Hyoung; Cho, Young-Lae; Lee, Won-Pyo; Suh, Su-Jeong

    2014-11-01

    Perpendicular magnetic recording (PMR) is a promising candidate for high density magnetic recording and has already been applied to hard disk drive (HDD) systems. However, media noise still limits the recording density. To reduce the media noise and achieve a high signal-to-noise ratio (SNR) in hard disk media, the grains of the magnetic layer must be magnetically isolated from each other. This study examined whether sputter-deposited Co-Pt thin films can have adjacent grains that are physically isolated. To accomplish this, the effects of the sputtering conditions and wet etching process on magnetic properties and the microstructure of the films were investigated. The film structure was Co-Pt (30 nm)/Ru (30 nm)/NiFe (10 nm)/Ta (5 nm). The composition of the Co-Pt thin films was Co-30.7 at.% Pt. The Co-Pt thin films were deposited in Ar gas at 5, 10, 12.5, and 15 mTorr. Wet etching process was performed using 7% nitric acid solution at room temperature. These films had high out-of-plane coercivity of up to 7032 Oe, which is twice that of the as-deposited film. These results suggest that wet etched Co-Pt thin films have weaker exchange coupling and enhanced out-of-plane coercivity, which would reduce the medium noise.

  16. High-performance PMN-PT thick films.

    Science.gov (United States)

    Kosec, Marija; Ursic, Hana; Holc, Janez; Hrovat, Marko; Kuscer, Danjela; Malic, Barbara

    2010-10-01

    This article describes some of our work on ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃ (0.65PMN-0.35PT) thick films printed on alumina substrates. These thick films, with the nominal composition ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃, were produced by screen-printing and firing a paste prepared from an organic vehicle and pre-reacted fine particles of avery chemically homogeneous powder. To improve the adhesion of the 0.65PMN-0.35PT to the platinized alumina substrate,a Pb(Zr₀.₅₃Ti₀.₄₇)O₃ layer was deposited between the electrode and the substrate. The samples were then sintered at 950 °C for 2 h with various amounts of packing powder on the alumina (Al₂O₃) substrates. The sintering procedure was optimized to obtain dense 0.65PMN-0.35PT films. The films were then characterized using scanning electron microscopy as well as measurements of the dielectric and piezoelectric constants.The electrostrictive behavior of the 0.65PMN-0.35PT thick films was investigated using an atomic force microscope(AFM). Finally, substrate-free, large-displacement bending type actuators were prepared and characterized, and the normalized displacement (i.e., the displacement per unit length) of the actuators was determined to be 55 μm/cm at 3.6 kV/cm.

  17. Co oxidation on spontaneous Pt-Ru deposits on composite polymeric electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bavio, M.A.; Kessler, T. [Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional del Centro de la Provincia de Buenos Aires, Av. del Valle 5737, B7400JWI, Olavarria (Argentina); Castro Luna, A.M. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas, INIFTA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Diagonal 113 y 64, 1900, La Plata (Argentina)

    2010-06-15

    Composite polyaniline electrodes containing carbon nanotubes incorporated in the film and spontaneous Pt-Ru deposits as catalytic material for CO oxidation are reported. PANI films were electrosynthesized from a monomer acid solution with the addition of carbon nanotubes. Then, Pt-Ru deposits were obtained by immersing the polymeric film in H{sub 2}PtCl{sub 6} and/or RuCl{sub 3} in HCl. Three series of deposits were prepared by either immersion in a solution containing both metallic ions during a fixed time or successive immersion in different solutions containing only one of the metallic ions during half of the established time and varying the sequence as follows: (i) first in H{sub 2}PtCl{sub 6} and then in RuCl{sub 3} or (ii) first in RuCl{sub 3} and then in H{sub 2}PtCl{sub 6}. Adsorbed CO oxidation was studied by cyclic voltammetry in H{sub 2}SO{sub 4} solution. The electrodes were characterized through SEM and EDX. The different ways to obtain spontaneous Pt-Ru deposits are analyzed and their influence on CO oxidation is discussed. (author)

  18. Magnetic properties and microstructure of FePt/MoC/CrRu films

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Jai-Lin, E-mail: tsaijl@dragon.nchu.edu.tw; Luo, Qi-Shao; Chen, Po-Ran; Tseng, Yun-Ting

    2015-05-15

    The FePt films with thickness of 4−10 nm were deposited on MoC/CrRu/glass at substrate temperature ranged from 260 to 410 °C by using magnetron sputtering and strong (001) textured FePt films were obtained at 380 °C and 410 °C. The multi-functional MoC conductive intermediate layer was used to resist the Cr diffusion and promote the epitaxial growth of the (001) textured FePt film which shows perpendicular magnetization and a linear-like in-plane magnetic loop. The out-of plane coercivity and shape of demagnetization curve were dominated by the ordering degree and perpendicular magnetic anisotropy which were increased with deposited temperature. The FePt film deposited at 290 °C shows continuous morphology and change to interconnected structure at 350 °C and finally form the island like structure at 380 °C and 410 °C. Each island contains many FePt grains and the smaller grains size was 12.2 nm which obtained at 5 nm thick FePt film. Perpendicular anisotropy of 1.1×10{sup 7} erg/cm{sup 3} and coercivity of 8.2 kOe have been demonstrated in 7 nm thick FePt film. - Highlights: • The MoC conductive intermediate layer was resisted the Cr diffusion. • The MoC layer promote the epitaxial growth of (001) textured FePt film. • The FePt film shows perpendicular magnetization on MoC layer.

  19. Microstructures and magnetic properties of [SiO2/FePt]5/Ag thin films

    Institute of Scientific and Technical Information of China (English)

    FAN Jiu-ping; XU Xiao-hong; JIANG Feng-xian; TIAN Bao-qiang; WU Hai-shun

    2008-01-01

    [SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO2/FePt]5/Ag films are changed into L10 and (111) mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controllingSiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 (0. 6nm)/FePt (3 nm)]5/Ag (50 nm) films and highly (001)-oriented films can be obtained in the [SiO2 (2 nm)/FePt (3 nm)]5/Ag (50 nm) films.

  20. Structure and electrical properties of PZT/LNO/PT multilayer films on stainless steel substrates

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    PbZr0.53Ti0.47O3 (PZT) ferroelectric thin films were deposited on LaNiO3 (LNO) by sol-gel method. The PbTiO3 (PT) seed layer was depos-ited between the LNO buffer layer and stainless steel (SS) substrate, which effectively decreased the annealing temperature of LNO layer from 750 C to 650 C. X-ray diffraction (XRD) reveals that LNO layers with PT layer crystallize into a perovskite phase on annealing at 650 C for 10 min. PZT deposited on LNO buffer layer with PT seed layer exhibits good ferroelectric proper...

  1. Magnetic Properties and Microstructure of FeOx/Fe/FePt and FeOx/FePt Films

    Directory of Open Access Journals (Sweden)

    Jai-Lin Tsai

    2013-01-01

    Full Text Available The Fe(6 nm/FePt film with perpendicular magnetization was deposited on the glass substrate. To study the oxygen diffusion effect on the coupling of Fe/FePt bilayer, the plasma oxidation with 0.5~7% oxygen flow ratio was performed during sputtered part of Fe layer and formed the FeOx(3 nm/Fe(3 nm/FePt trilayer. Two-step magnetic hysteresis loops were found in trilayer with oxygen flow ratio above 1%. The magnetization in FeOx and Fe/FePt layers was decoupled. The moments in FeOx layer were first reversed and followed by coupled Fe/FePt bilayer. The trilayer was annealed again at 500°C and 800°C for 3 minutes. When the FeOx(3 nm/Fe(3 nm/FePt trilayer was annealed at 500°C, the layers structure was changed to FeOx(6 nm/FePt bilayer due to oxygen diffusion. The hard-magnetic FeOx(6 nm/FePt film was coupled with single switching field. The FeOx/(disordered FePt layer structure was observed with further annealing at 800°C and presented soft-magnetic loop. In summary, the coupling between soft-magnetic Fe, FeOx layer, and hard-magnetic L10 FePt layer can be controlled by the oxygen diffusion behavior, and the oxidation of Fe layer was tuned by the annealing temperature. The ordered L10 FePt layer was deteriorated by oxygen and became disordered FePt when the annealed temperature was up to 800°C.

  2. Evidence of a Surface-Mediated Magnetically Induced Miscibility Gap in Co-Pt Alloy Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Rooney, P.W.; Shapiro, A.L.; Tran, M.Q.; Hellman, F. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

    1995-08-28

    (100) and (111) oriented single-crystal CoPt{sub 3} films were deposited over a range of growth temperatures from {minus}50 to 800 {degree}C. The Curie temperature is increased by 200 {degree}C over the value expected for the homogeneous alloy in the as-deposited films (of both orientations) grown near 400 {degree}C. We interpret this as evidence for a previously unobserved, surface-mediated, magnetically driven miscibility gap in vapor-deposited CoPt{sub 3} films. Large perpendicular magnetic anisotropy is also observed in the as-deposited films (of both orientations) grown near 400 {degree}C.

  3. The Underpotential Deposition of Copper on Pt(311): Site Selective Deposition and Anion Effects

    Science.gov (United States)

    1994-03-14

    AD-A278 022 OFFICE OF NAVAL RESEARCH CONTRACT N00014-84-k-0656/PP0002 R & T Code 4133034 Technical Report #36 The Underpotential Deposition of Copper...Include Security Clauffication) The Underpotential Deposition of Copper on Pt(311): Site Selective Deposition and Anion Effects 𔃼 OERSONAL AUTHOR(S...Alacant, Spain ABSTRACT The underpotential deposition of copper on Pt(31 1)=Pt[2(111 )x(100)] stepped surfaces has been studied and the results are compared

  4. Dependence of Magnetic Properties of Co/Pt Multilayers on Deposition Temperature of Pt Buffer Layers

    Science.gov (United States)

    Shiomi, Shigeru; Nishimura, Tomotaka; Kobayashi, Tadashi; Masuda, Morio

    1993-04-01

    A 15-nm-thick Pt buffer layer was deposited on a glass slide at temperature Ts(Ptbuf) ranging from 30 to 300°C by e-gun evaporation. Following the cooling in vacuum to ambient temperature, Co and Pt layers have been alternately deposited on it. Very large perpendicular anisotropy and coercivity have been obtained at Ts(Ptbuf) higher than 200°C. The (111) preferred orientation of the Co/Pt multilayer as well as the Pt buffer layer became more pronounced with elevating Ts(Ptbuf), to which the enhancement of perpendicular anisotropy with elevating Ts(Ptbuf) might be ascribable.

  5. Thin Film Deposition Techniques (PVD)

    Science.gov (United States)

    Steinbeiss, E.

    The most interesting materials for spin electronic devices are thin films of magnetic transition metals and magnetic perovskites, mainly the doped La-manganites [1] as well as several oxides and metals for passivating and contacting the magnetic films. The most suitable methods for the preparation of such films are the physical vapor deposition methods (PVD). Therefore this report will be restricted to these deposition methods.

  6. Effects of Ag addition on FePt L10 ordering transition: A direct observation of ordering transition and Ag segregation in FePtAg alloy films

    Science.gov (United States)

    Wang, Lei; Gao, Tenghua; Yu, Youxing

    2015-12-01

    FePt and (FePt)91.2Ag8.8 alloy films were deposited by magnetron sputtering. The average coercivity of (FePt)91.2Ag8.8 films reaches 8.51 × 105 A/m, which is 0.63 × 105 A/m higher than that of the corresponding FePt films. Ag addition effectively promotes the FePt L10 ordering transition at a relatively low annealing temperature of 400 °C. The promotion mechanism was investigated by using in situ high-resolution transmission electron microscopy (HRTEM) and ex situ X-ray absorption fine structure (XAFS). The concurrence of ordering transition and Ag segregation in FePtAg alloy films was first observed by using in situ heating HRTEM. The time-resolved evolution reveals more details on the role of Ag addition in FePt low-temperature ordering. Ex situ XAFS results further confirm that Ag replaces Fe sites in the as-deposited films and segregates from FePt-Ag solid solution phase through annealing at elevated temperatures. The segregation of Ag atoms leaves vacancies in the grain. The vacancy formation is believed to accelerate the diffusion of Fe and Pt atoms, which is critical for the L10 ordering transition.

  7. Room-temperature formation of Pt$_3$Si/Pt$_2$Si films on poly-Si substrates

    CERN Document Server

    Dubkov, V P; Chizh, K V; Yuryev, V A

    2016-01-01

    We propose a way of formation of thin bilayer Pt$_3$Si/Pt$_2$Si films at room temperature on poly-Si substrates by Pt magnetron sputtering and wet etching, obtain such film, investigate its structure and phase composition and estimate the thickness of its layers. We verify by direct x-ray photoelectron-spectroscopic measurements our previous observation of the Pt$_2$Si layer formaton between Pt and poly-Si films as a result of Pt magnetron sputtering at room temperature. This layer likely appears due to high enough temperature of Pt ions in the magnetron plasma sufficient for chemical reaction of the silicide film formation on the Si surface. The Pt$_3$Si layer likely forms from the Pt--Pt$_3$Si layer (Pt$_{95}$Si$_5$), which arises under Pt film during the magnetron sputtering, as a result of Pt removal by wet etching.

  8. Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2 Film

    Directory of Open Access Journals (Sweden)

    Chun He

    2009-01-01

    Full Text Available A series of Pt-TiO2 films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2 films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2 films was evaluated in the photocatalytic (PC and photoelectrocatalytic (PEC degradation of formic acid in aqueous solution. Compared with a TiO2 film, the efficiency of formic acid degradation using the Pt-TiO2 films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on the TiO2 surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt-TiO2 films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

  9. Tuning the magnetic properties of Fe50-xMnxPt50 thin films

    Science.gov (United States)

    Manoharan, Ezhil A.; Mankey, Gary; Hong, Yang-Ki

    2017-09-01

    The magnetic and structural properties of highly ordered (S ∼ 0.82) epitaxial Fe50-xMnxPt50 thin films were investigated. L10 Fe50-xMnxPt50 (x = 0, 6, 9, 12 and 15) thin films with a constant thickness of 45 nm were prepared by co-sputtering Fe50Pt50 and Mn50Pt50 on to MgO (100) single crystal substrate. We find a significant increase in the coercivity for FeMnPt thin films. We have shown that this increase coincides with a tetragonal distortion, while a recent first principles study of Mn doped FePt showed the sub lattice ordering of ferromagnetically aligned Mn atoms would lead to increase in magnetic anisotropy in the FeMnPt ternary alloy system with fixed Pt concentration. At x = 12 the coercivity has increased by 46.4% relative to that of Fe50Pt50 (x = 0). We attribute the increase in coercivity to the tetragonal distortion as the experimentally determined c/a ratio is larger than the expected c/a ratio for ferromagnetically ordered Mn atoms in the sublattice at the concentration x = 12. High temperature deposition and high temperature annealing was applied to achieve large coercivity in Mn doped FePt as these process lead to the observed tetragonal distortion.

  10. Development of Nanostructured Stress Free Pt-Rich FePt Films for Micro Electro Mechanical System Applications

    Directory of Open Access Journals (Sweden)

    T. M. Selvakumari

    2009-01-01

    Full Text Available Problem statement: The electroplating technique is especially interesting due to its low cost, high throughput and high quality of deposit. Magnetic thin films are extensively used in various electronic devices including high density recording media and Micro Electro Mechanical (MEMS devices. So we examined FePt films and give good magnetic properties. Approach: The Pt-rich FePt alloys were electrodeposited galvanostatically by various temperature baths. Results: The elemental percentage of Pt in the film was very high determined by X-ray spectroscopy. Surface characterization was carried out by using X-Ray Diffractometer (XRD and Scanning Electron Microscope (SEM.The magnetic properties determined by Vibrating sample magnetometer. Hardness and adhesion of the films were also discussed. Conclusion/Recommendation: The films were soft magnetic character of lower temperature bath and become a hard magnetic character of higher temperature bath. Therefore this magnetic films could be an important material for incorporate in Micro electro mechanical devices.

  11. Variable temperature semiconductor film deposition

    Science.gov (United States)

    Li, Xiaonan; Sheldon, Peter

    1998-01-01

    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  12. Structural transformation of FePt nanocomposite films during annealing and its effects on magnetic properties

    Institute of Scientific and Technical Information of China (English)

    ZHAN Xiaoyuan; ZHANG Yue; GU Yousong; LI Jianmin

    2006-01-01

    Fe100-xPtx(x=30at.%-60at.% ) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.

  13. Immersion Deposition of Pt Nanoparticles on Porous Silicon for Methanol Oxidation

    Institute of Scientific and Technical Information of China (English)

    SU Xu; LU Kangle; CHANG Yanlong; ZHANG Yan; WANG Chunming

    2009-01-01

    Porous silicon(PS)was chosen as the substrate for supporting the Pt particles because of great surface area,good conductivity and stability.Pt nanoparticles have been successfully prepared on the substrate by immersion deposition,which is convenient.The component and morphological properties of the films have been investigated by means of X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDX)and scanning electron microscopy(SEM),which shows that the Pt particles have small size and big specific surface.Cyclic voltammetry(CV)research showed that the Pt nanoparticles had novel catalytic activity for methanol when the immersion deposition time was past 24 min.

  14. Laser-assisted preparation and photoelectric properties of grating-structured Pt/FTO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nai-fei, E-mail: rnf_ujs@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Huang, Li-jing, E-mail: lij_huang@126.com [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Bao-jia [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Ming [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-09-30

    Highlights: • Pt layers were deposited by DC magnetron sputtering on commercial FTO glasses. • Pt/FTO films were irradiated by laser for inducing gratings and annealing. • An ideal grating-structured Pt/FTO film was obtained using a fluence of 1.05 J/cm{sup 2}. • The grating-structured Pt/FTO film exhibited excellent photoelectric properties. • Laser-assisted treatment is effective for improving performance of FTO-based films. - Abstract: In order to improve the transparency and conductivity of commercial fluorine-doped tin oxide (FTO) glass, platinum (Pt) layers were deposited on the FTO film by direct current (DC) magnetron sputtering, followed by being irradiating with a 532 nm nanosecond pulsed laser for the dual purpose of inducing grating structures and annealing. Introducing a Pt layer decreased the average transmittance (400–800 nm) and the sheet resistance of the initial FTO film from 80.2% and 8.4 Ω/sq to 68.6% and 7.9 Ω/sq, respectively. The ideal grating-structured Pt/FTO film was obtained by laser irradiation with a fluence of 1.05 J/cm{sup 2}, and X-ray diffraction (XRD) analysis confirmed that this film underwent optimal annealing. As a result, it exhibited an average transmittance (400–800 nm) of 84.1% and a sheet resistance of 6.8 Ω/sq. These results indicated that laser-assisted treatment combined with introduction of metal layer can effectively improve photoelectric properties of FTO single-layer films.

  15. Nanoscaled alloy formation from self-assembled elemental Co nanoparticles on top of Pt films

    Directory of Open Access Journals (Sweden)

    Luyang Han

    2011-08-01

    Full Text Available The thermally activated formation of nanoscale CoPt alloys was investigated, after deposition of self-assembled Co nanoparticles on textured Pt(111 and epitaxial Pt(100 films on MgO(100 and SrTiO3(100 substrates, respectively. For this purpose, metallic Co nanoparticles (diameter 7 nm were prepared with a spacing of 100 nm by deposition of precursor-loaded reverse micelles, subsequent plasma etching and reduction on flat Pt surfaces. The samples were then annealed at successively higher temperatures under a H2 atmosphere, and the resulting variations of their structure, morphology and magnetic properties were characterized. We observed pronounced differences in the diffusion and alloying of Co nanoparticles on Pt films with different orientations and microstructures. On textured Pt(111 films exhibiting grain sizes (20–30 nm smaller than the particle spacing (100 nm, the formation of local nanoalloys at the surface is strongly suppressed and Co incorporation into the film via grain boundaries is favoured. In contrast, due to the absence of grain boundaries on high quality epitaxial Pt(100 films with micron-sized grains, local alloying at the film surface was established. Signatures of alloy formation were evident from magnetic investigations. Upon annealing to temperatures up to 380 °C, we found an increase both of the coercive field and of the Co orbital magnetic moment, indicating the formation of a CoPt phase with strongly increased magnetic anisotropy compared to pure Co. At higher temperatures, however, the Co atoms diffuse into a nearby surface region where Pt-rich compounds are formed, as shown by element-specific microscopy.

  16. films using atomic layer deposition

    Science.gov (United States)

    Chervinskii, Semen; Matikainen, Antti; Dergachev, Alexey; Lipovskii, Andrey A.; Honkanen, Seppo

    2014-08-01

    We fabricated self-assembled silver nanoisland films using a recently developed technique based on out-diffusion of silver from an ion-exchanged glass substrate in reducing atmosphere. We demonstrate that the position of the surface plasmon resonance of the films depends on the conditions of the film growth. The resonance can be gradually shifted up to 100 nm towards longer wavelengths by using atomic layer deposition of titania, from 3 to 100 nm in thickness, upon the film. Examination of the nanoisland films in surface-enhanced Raman spectrometry showed that, in spite of a drop of the surface-enhanced Raman spectroscopy (SERS) signal after the titania spacer deposition, the Raman signal can be observed with spacers up to 7 nm in thickness. Denser nanoisland films show slower decay of the SERS signal with the increase in spacer thickness.

  17. Spin Hall effects in mesoscopic Pt films with high resistivity

    Science.gov (United States)

    Qin, Chuan; Luo, Yongming; Zhou, Chao; Cai, Yunjiao; Jia, Mengwen; Chen, Shuhan; Wu, Yizheng; Ji, Yi

    2016-10-01

    The energy efficiency of the spin Hall effects (SHE) can be enhanced if the electrical conductivity is decreased without sacrificing the spin Hall conductivity. The resistivity of Pt films can be increased to 150-300 µΩ · cm by mesoscopic lateral confinement, thereby decreasing the conductivity. The SHE and inverse spin Hall effects (ISHE) in these mesoscopic Pt films are explored at 10 K by using the nonlocal spin injection/detection method. All relevant physical quantities are determined in situ on the same substrate, and a quantitative approach is developed to characterize all processes effectively. Extensive measurements with various Pt thickness values reveal an upper limit for the Pt spin diffusion length: {λ\\text{pt}}   ⩽  0.8 nm. The average product of {λ\\text{pt}} and the Pt spin Hall angle {α\\text{H}} is substantial: {α\\text{H}}{λ\\text{pt}}   =  (0.142  ±  0.040) nm for 4 nm thick Pt, though a gradual decrease is observed at larger Pt thickness. The results suggest enhanced spin Hall effects in resistive mesoscopic Pt films.

  18. Electrically programmable-erasable In-Ga-Zn-O thin-film transistor memory with atomic-layer-deposited Al{sub 2}O{sub 3}/Pt nanocrystals/Al{sub 2}O{sub 3} gate stack

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Shi-Bing; Zhang, Wen-Peng; Liu, Wen-Jun; Ding, Shi-Jin, E-mail: sjding@fudan.edu.cn [State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433 (China)

    2015-12-15

    Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) memory is very promising for transparent and flexible system-on-panel displays; however, electrical erasability has always been a severe challenge for this memory. In this article, we demonstrated successfully an electrically programmable-erasable memory with atomic-layer-deposited Al{sub 2}O{sub 3}/Pt nanocrystals/Al{sub 2}O{sub 3} gate stack under a maximal processing temperature of 300 {sup o}C. As the programming voltage was enhanced from 14 to 19 V for a constant pulse of 0.2 ms, the threshold voltage shift increased significantly from 0.89 to 4.67 V. When the programmed device was subjected to an appropriate pulse under negative gate bias, it could return to the original state with a superior erasing efficiency. The above phenomena could be attributed to Fowler-Nordheim tunnelling of electrons from the IGZO channel to the Pt nanocrystals during programming, and inverse tunnelling of the trapped electrons during erasing. In terms of 0.2-ms programming at 16 V and 350-ms erasing at −17 V, a large memory window of 3.03 V was achieved successfully. Furthermore, the memory exhibited stable repeated programming/erasing (P/E) characteristics and good data retention, i.e., for 2-ms programming at 14 V and 250-ms erasing at −14 V, a memory window of 2.08 V was still maintained after 10{sup 3} P/E cycles, and a memory window of 1.1 V was retained after 10{sup 5} s retention time.

  19. High-performance energy harvester fabricated with aerosol deposited PMN-PT material

    Science.gov (United States)

    Chen, C. T.; Lin, S. C.; Lin, T. K.; Wu, W. J.

    2016-11-01

    This paper reports a high-performance piezoelectric energy harvester (EH) fabricated with xPb(Mg1/3Nb2/3)-(l-x)PbTiO3 (PMN-PT) by aerosol deposition method. The result indicates that PMN-PT based EH owns 1.8 times output power which is higher than traditional PbZrxTi1- xO3 (PZT) based EH. In order to compare the output performance of EH fabricated with PMN- PT compared with PZT, the similar thickness of PMN-PT and PZT thin film is deposited on stainless steel subtracted. The experimental results show that PZT-based EH had a maximum output power of 4.65 μW with 1.11 Vp-p output voltage excited at 94.4 Hz under 0.5g base excitation, while the PMN-PT based device has a maximum output power of 8.42 μW with 1.49 Vp-p output voltage at a vibration frequency of 94.8 Hz and the same base excitation level. The volumetric power density was 82.95 μW/mm3 and 48.05 μW/mm3 for the device based on PMN- PT and PZT materials, respectively. All the results demonstrate that PMN-PT has better output performance than PZT.

  20. Nanofriction properties of molecular deposition films

    Institute of Scientific and Technical Information of China (English)

    王强斌; 高芒来; 张嗣伟

    2000-01-01

    The nanofriction properties of Au substrate and monolayer molecular deposition film and multilayer molecular deposition films on Au substrate and the molecular deposition films modified with alkyl-terminal molecule have been investigated by using an atomic force microscope. It is concluded that ( i ) the deposition of molecular deposition films on Au substrate and the modification of alkyl-terminal molecule to the molecular deposition films can reduce the frictional force; (ii) the molecular deposition films with the same terminal exhibit similar nanofriction properties, which has nothing to do with the molecular chain-length and the layer number; (iii) the unstable nanofriction properties of molecular deposition films are contributed to the active terminal of the molecular deposition film, which can be eliminated by decorating the active molecular deposition film with alkyl-terminal molecule, moreover, the decoration of alkyl-terminal molecule can lower the frictional force conspicuously; (iv) the relat

  1. Magnetoelastically induced perpendicular magnetic anisotropy and perpendicular exchange bias of CoO/CoPt multilayer films

    Science.gov (United States)

    Guo, Lei; Wang, Yue; Wang, Jian; Muraishi, Shinji; Sannomiya, Takumi; Nakamura, Yoshio; Shi, Ji

    2015-11-01

    The effects of magnetoelastically induced perpendicular magnetic anisotropy (PMA) on perpendicular exchange bias (PEB) have been studied in [CoO5nm/CoPt5nm]5 multilayer films. After deposition at room temperature, [CoO5nm/CoPt5nm]5 multilayer films were post-annealed at 100 °C, 250 °C, 300 °C and 375 °C for 3 h. In-plane tensile stress of CoPt layer was calculated by sin2 φ method, and we found it increased gradually upon annealing from 0.99 GPa (as-deposited) up to 3.02 GPa (300 °C-annealed). As to the magnetic property, significant enhancement of PMA was achieved in [CoO5nm/CoPt5nm]5 multilayer films after annealing due to the increase of CoPt layer in-plane tensile stress. With the enhancement of magnetoelastically induced PMA, great improvement of PEB was also achieved in [CoO5nm/CoPt5nm]5 multilayer films, which increased from 130 Oe (as-deposited) up to 1060 Oe (300 °C-annealed), showing the same change tendency as PMA and the strong correlation with CoPt layer in-plane tensile stress. We consider it is the increase of CoPt layer in-plane tensile stress that leads to the enhancement of CoPt layer PMA, which is favorable for the spins in CoPt layer aligning to a more perpendicular direction. And thus the enhanced PMA with more perpendicular spins alignment in CoPt layer results in the improved PEB in [CoO5nm/CoPt5nm]5 multilayer films through enhanced perpendicular spins coupling at CoO/CoPt interfaces.

  2. Microstructure and Electrical Properties of PMN-PT Thin Films Prepared by Oxygen Plasma Assisted Pulsed Laser Deposition%氧等离子体辅助脉冲激光沉积法制备PMN-PT薄膜的微观结构和电学性能

    Institute of Scientific and Technical Information of China (English)

    何邕; 李效民; 高相东; 冷雪; 王炜

    2011-01-01

    Lead magnesium niobate-lead titanate (PMN-PT) ferroelectric thin films with composition near the morphotropic phase boundary (MPB) were deposited on Si substrate by oxygen plasma assisted pulsed laser deposition (PLD).Highly (001)-oriented PMN-PT thin films with lower oxygen defect and higher crystalline property were obtained.The results show that the microstructure and electrical properties of PMN-PT thin films strongly depend on the partial pressure and the activity of oxygen in the deposition process.With the use of oxygen plasma,the dielectric constant of the PMN-PT thin film is increased from 1484 to 3012,the remnant polarization (2Pr) changes from 18μC/cm2 to 38 μC/cm2.%采用氧等离子体辅助脉冲激光沉积方法(PLD)在硅衬底上,制备出高度(001)取向的钙钛矿相结构钛铌镁酸铅(PMN-PT)薄膜.研究了氧等离子体辅助对PMN-PT薄膜相结构、微观形貌和电学性能的影响.结果表明,通过在薄膜沉积过程中引入高活性的氧等离子,可以有效地提高PMN-PT薄膜的结晶质量和微观结构.未采用氧等离子体辅助PLD方法制备PMN-PT薄膜的介电常数(10 kHz)和剩余极化(2Pr)分别为1484和18 μC/cm2,通过采用氧等离子体辅助,其介电常数和剩余极化分别提高至3012和38 μC/cm2.

  3. Perpendicular magnetic anisotropy in Co{sub 3}Pt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, Christian; Makarov, Denys; Brombacher, Christoph; Neupert, Katja; Kehr, Mirko; Hoyer, Walter; Albrecht, Manfred [Chemnitz University of Technology (Germany). Institute of Physics

    2010-07-01

    Binary alloys of M{sub x}Pt{sub 1-x} (M=Fe and Co) prepared as thin films tend to show a strong perpendicular magnetic anisotropy (PMA), making them good candidates for magnetic recording media or sensoric devices. The magnetic response of M{sub x}Pt{sub 1-x} films can be strongly modified by the degree of composition, film thickness, deposition temperature, and nature of substrate. Thus, chemically disordered CoPt alloys with (111) texture exhibit an unexpected PMA related to an anisotropic short-range order (SRO) effect. Here we present an investigation of structural and magnetic properties of Co{sub 3}Pt alloy films in the thickness range from 5 to 20 nm. The magnetic layers were deposited using magnetron co-sputtering on thermally oxidized Si(100) wafers. Interestingly, even when deposited at room temperature, these films reveal the presence of a strong PMA (K{sub U} = 0.6 MJ/m{sup 3}) with a full remanence in the out-of-plane direction. Furthermore, owing to the high Co content, the alloy has a rather high value of saturation magnetization of about 0.8 T. To access the structural properties of the alloy, a X-ray diffraction study was carried out. However, no superstructure peaks which might be attributed to a chemical long range order have been observed indicating that SRO is the origin for the PMA.

  4. Platinum containing amorphous hydrogenated carbon (a-C:H/Pt) thin films as selective solar absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Yung-Hsiang; Brahma, Sanjaya [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Tzeng, Y.H. [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Ting, Jyh-Ming, E-mail: jting@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan (China)

    2014-10-15

    We have investigated a double-cermet structured thin film in which an a-C:H thin film was used as an anti-reflective (AR) layer and two platinum-containing amorphous hydrogenated carbon (a-C:H/Pt) thin films were used as the double cermet layers. A reactive co-sputter deposition method was used to prepare both the anti-reflective and cermet layers. Effects of the target power and heat treatment were studied. The obtained films were characterized using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy. The optical absorptance and emittance of the as deposited and annealed films were determined using UV–vis-NIR spectroscopy. We show that the optical absorptance of the resulting double-cermet structured thin film is as high as 96% and remains to be 91% after heat treatment at 400 °C, indicating the thermal stability of the film.

  5. Room temperature sensing of O2 and CO by atomic layer deposition prepared ZnO films coated with Pt nanoparticles

    NARCIS (Netherlands)

    Erkens, I.J.M.; Blauw, M.A.; Verheijen, M.A.; Roozeboom, F.; Kessels, W.M.M.

    2013-01-01

    Ultralow-power gas sensing devices need to operate without an energy consuming heater element. This requires the design of sensing devices that are so efficient that they can operate at room temperature (RT). Here, we report on the RT sensing performance of atomic layer deposition (ALD) prepared i-Z

  6. Electrocaloric effect of PMN–PT thin films near morphotropic phase boundary

    Indian Academy of Sciences (India)

    D Saranya; Ayan Roy Chaudhuri; Jayanta Parui; S B Krupanidhi

    2009-06-01

    The electrocaloric effect is calculated for PMN–PT relaxor ferroelectric thin film near morphotropic phase boundary composition. Thin film of thickness, ∼ 240 nm, has been deposited using pulsed laser deposition technique on a highly (111) oriented platinized silicon substrate at 700°C and at 100 mtorr oxygen partial pressure. Prior to the deposition of PMN–PT, a template layer of LSCO of thickness, ∼ 60 nm, is deposited on the platinized silicon substrate to hinder the pyrochlore phase formation. The temperature dependent P–E loops were measured at 200 Hz triangular wave operating at the virtual ground mode. Maximum reversible adiabatic temperature change, = 31 K, was calculated at 140°C for an external applied voltage of 18 V.

  7. Magnetic Properties and Nanostructures of FePtCu:C Thin Films with FePt Underlayers

    Institute of Scientific and Technical Information of China (English)

    JIN Ling-Fang; YAN Ming-Lang

    2007-01-01

    Magnetic properties and nanostructures of FePtCu:C thin films with FePt underlayers (ULs) are studied. The effect of FePt ULs on the orientation and magnetic properties of the thin films are investigated by adjusting FePt UL thicknesses from 2nm to 14nm. X-ray diffraction (XRD) scans reveal that the orientation of the films is dependent on FePt UL thickness. For a 5-nm FePtCu:C nanocomposite thin film with a 2-nm FePt UL, the coercivity is 6.5 KOe, the correlation length is 59nm, the desired face-centred-tetragonal (fct) ordered structure [L10 phase] is formed and the c axis normal to the film plane [(001) texture] is obtained. These results indicate that the better orientation and magnetic properties of the films can be tuned by decreasing the thickness of the FePt UL.

  8. Effect of substrates on phase formation in PMN-PT 68/32 thin films by sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. [Department of Physics, National Institute of Technology, Rourkela 769008 (India)], E-mail: pvn77@rediffmail.com; Sonia; Patel, R.K. [Department of Chemistry, National Institute of Technology, Rourkela 769008 (India); Prakash, C. [DRDO Bhawan, Rajaji Marg, New Delhi 110011 (India); Goel, T.C. [BITS Pilani-Goa Campus, Goa 403720 (India)

    2008-07-15

    PMN-PT 68/32 thin films have been prepared on Pt/Si, ITO coated glass, stainless steel and silicon substrates in the identical processing conditions by sol-gel process. Annealing temperature of 600 deg. C was ascertained by thermo gravimetric analysis (TGA) study of the dried sol-gel powder of PMNT-PT 68/32 composition. X-ray diffraction (XRD) study showed {approx}95% perovskite phase formation on Pt/Si and ITO coated glass substrates. SEM micrographs showed the formation of sub micron size grains on Pt/Si and ITO coated glass substrates. Diffuse phase transition with transition temperature (T{sub c}) {approx}190 deg. C was observed in 0.8 {mu}m thick PMN-PT 68/32 films deposited on Pt/Si and ITO coated glass substrates.

  9. A study on the microstructure of Pt/TaN/Si films by high resolution TEM analysis

    CERN Document Server

    Cho, K N; Oh, J E; Park, C S; Lee, S I; Lee, M Y

    1998-01-01

    The microstructure change of Pt/amorphous TaN/Si films after various heat treatments has been investigated by high resolution transmission electron microscopy (HR-TEM) analysis. TaN thin films are deposited by remote plasma metalorganic chemical vapor deposition (RP-MOCVD) using pentakis-dimethyl-amino-tantalum (PDMATa) and radical sources, hydrogen and ammonia plasma. Deposited TaN thin film shows excellent barrier properties such as good resistance against oxidation after post-heat treatment at high temperature. In the case of hydrogen plasma, however, diffusion of Pt into TaN layer was observed, which was caused by the out-diffusion of carbon through the grain boundaries of Pt. In the case of ammonia plasma, the formation of thin oxide layer at the Pt/TaN interface was observed.

  10. Deposition of antimony telluride thin film by ECALE

    Institute of Scientific and Technical Information of China (English)

    GAO; Xianhui; YANG; Junyou; ZHU; Wen; HOU; Jie; BAO; Siqian; FAN; Xi'an; DUAN; Xingkai

    2006-01-01

    The process of Sb2Te3 thin film growth on the Pt substrate by electrochemical atomic layer epitaxy (ECALE) was studied. Cyclic voltammetric scanning was performed to analyze the electrochemical behavior of Te and Sb on the Pt substrate. Sb2Te3 film was formed using an automated flow deposition system by alternately depositing Te and Sb atomic layers for 400 circles. The deposited Sb2Te3 films were characterized by XRD, EDX, FTIR and FESEM observation. Sb2Te3 compound structure was confirmed by XRD pattern and agreed well with the results of EDX quantitative analysis and coulometric analysis. FESEM micrographs showed that the deposit was composed of fine nano particles with size of about 20 nm. FESEM image of the cross section showed that the deposited films were very smooth and dense with thickness of about 190 nm. The optical band gap of the deposited Sb2Te3 film was determined as 0.42 eV by FTIR spectroscopy, and it was blue shifted in comparison with that of the bulk Sb2Te3 single crystal due to its nanocrystalline microstructure.

  11. Structural and Magnetic Properties of FePt-C Nanocomposite Films

    Institute of Scientific and Technical Information of China (English)

    WANG Hao; YANG Fu-Jun; CHEN Kan-Song; ZHOU Bin; ZHANG Yuan-Wei; GU Hao-Shuang; CHIAH M. F.; CHEUNG W. Y.; WONG S. P.

    2004-01-01

    @@ Nanocomposite FePt-C thin films were prepared by a pulsed filtered vacuum arc deposition technique. The films were characterized by non-Rutherford backscattering spectrometry, x-ray diffraction, and magnetic force microscopy. The dependence of magnetic properties against annealing temperature was studied by using a vibrating sample magnetometer. Both x-ray diffraction and magnetic force microscopy analyses confirmed the formation of nano-crystallites of face-centred-tetragonal phase of FePt in the carbon matrix after annealing at a sufficiently high temperature. For the film with a composition of (Fe0.55Pt0.45)0.78C0.22, the coercivity and the grain size were observed to increase with increasing annealing temperature, up to a value of 3.5 kOe at an annealing temperature of 650℃, and with a grain size about 10. 5 nm.

  12. Effect of Ag underlayer on microstructures and perpendicular magnetic properties of CoPt nanocomposite thin films.

    Science.gov (United States)

    Shen, C L; Kuo, P C; Li, Y S; Lin, G P; Huang, K T; Ou, S L; Chen, S C

    2011-12-01

    CoPt/Ag films were prepared by magnetron sputtering on glass substrates and subsequent annealing. The dependence of degree of ordering and magnetic properties on Ag film thickness and annealing conditions were investigated. It was found that the Ag underlayer played a dominant role in inducing the (001) texture of the CoPt film after annealing. CoPt films with a thickness about 20 nm and Ag underlayers with a thickness about 70 nm are easy to obtain a large degree of ordering and a perpendicular magnetic anisotropy after annealing at 700 degrees C for 30 min. CoPt/Ag films with out-of-plane coercivity (Hc (perpendicular)) in the range of 13.5-14.0 kOe and a out-of-plane squareness (S(perpendicular)) of 0.97 were obtained after annealing at 700 degrees C for 30 min. Ag underlayer is beneficial to enhance the Hc(perpendicular)and S(perpendicular) of CoPt film significantly. The degree of ordering and perpendicular magnetic properties of the CoPt films which deposited on Ag underlayer are larger than those of the single layer CoPt films.

  13. Flame-Made Pt-Loaded TiO2 Thin Films and Their Application as H2 Gas Sensors

    Directory of Open Access Journals (Sweden)

    Weerasak Chomkitichai

    2013-01-01

    Full Text Available The hydrogen gas sensors were developed successfully using flame-made platinum-loaded titanium dioxide (Pt-loaded TiO2 nanoparticles as the sensing materials. Pt-loaded TiO2 thin films were prepared by spin-coating technique onto Al2O3 substrates interdigitated with Au electrodes. Structural and gas-sensing characteristics were examined by using scanning electron microscopy (SEM and showed surface morphology of the deposited film. X-ray diffraction (XRD patterns can be confirmed to be the anatase and rutile phases of TiO2. High-resolution transmission electron microscopy (HRTEM showed that Pt nanoparticles deposited on larger TiO2 nanoparticles. TiO2 films loaded with Pt nanoparticles were used as conductometric sensors for the detection of H2. The gas sensing of H2 was studied at the operating temperatures of 300, 350, and 400°C in dry air. It was found that 2.00 mol% Pt-loaded TiO2 sensing films showed higher response towards H2 gas than the unloaded film. In addition, the responses of Pt-loaded TiO2 films at all operating temperatures were higher than that of unloaded TiO2 film. The response increased and the response time decreased with increasing of H2 concentrations.

  14. Electrodeposition and electrocatalytic activity of Pt and Pt-alloy nanoparticles and thin films on highly oriented pyrolytic graphite (HOPG)

    Science.gov (United States)

    Lu, Guojin

    Pt and Pt-based alloy catalysts were synthesized by electrodeposition on HOPG. The nucleation and growth, morphology, composition and crystal structure, and electrocatalytic activity (towards relevant reactions in the frame of PEMFCs and DMFCs) of these model electrodes were systematically investigated. The presence of chlorides inhibits the Pt reduction processes. There is a transition from progressive to instantaneous nucleation with increasing overpotential for the deposition from 1 mM H2PtCl6 electrolytes. The possibility of instantaneous nucleation at large overpotential by using electrolytes with large chloride concentration is advantageous for the growth of small, well dispersed nanoparticles. The electrochemical data were confirmed by AFM and SEM imaging studies. Relatively narrow size distributed nanoparticles can be obtained from the current system. While MOR activity decreases with decreasing particle size, the HER and HOR activity of deposited Pt particles increases with decreasing deposition period. The ORR activity first increases then decreases with increasing deposition time. Interactions between Pt and Ru, or Ni or Co are observed and they form solid solution as verified by XRD. Underpotential deposition occurs for Pt-Ni or Pt-Co co-electrodeposition. Pt-Ru deposition can be described as progressive nucleation at low overpotential and instantaneous nucleation at high overpotentials. Through direct morphological observations, the Pt-Ni or Pt-Co nucleation can be approximately described as progressive. Pt-Ru deposits are superior to Pt towards MOR. The optimum Ru content is about 50 at.%. Pt-Ni and Pt-Co deposits are more active than Pt for ORR. The optimum content is about 30 at.% Ni or 50 at.% Co. Dealloying of Pt-Ru and Pt-Ni or Pt-Co electrodeposit is observed after electrochemical characterization. The extent of dealloying increases with the content of the alloying element.

  15. Polarization effect on the photocurrent of Pt sandwiched multi-crystalline ferroelectric films

    Energy Technology Data Exchange (ETDEWEB)

    Cao Dawei; Zhang Hui; Fang Liang; Dong Wen [Jiangsu Key Laboratory of Thin Films and Department of Physics, Soochow University, Suzhou 215006 (China); Zheng Fengang, E-mail: zhfg@suda.edu.cn [Jiangsu Key Laboratory of Thin Films and Department of Physics, Soochow University, Suzhou 215006 (China); Shen Mingrong, E-mail: mrshen@suda.edu.cn [Jiangsu Key Laboratory of Thin Films and Department of Physics, Soochow University, Suzhou 215006 (China)

    2011-10-03

    Highlights: {yields} Distinguish the two mechanisms of the polarization effect on photocurrent. {yields} Research the influence of the polarization charge near the interface. {yields} There is less study on the photovoltaic property of BNT films. - Abstract: Based on the analysis of the photocurrent behavior of the Pt sandwiched (Bi{sub 3.7}Nd{sub 0.3})Ti{sub 3}O{sub 12} (BNT) films deposited by sol-gel method, the mechanism of the polarization effect on the photocurrent of Pt sandwiched multi-crystalline ferroelectric films was clarified that, in ferroelectric films irradiated by the extra light, the depolarization field directly gives more contribution to the photocurrent when the polarization aligned under the external poling voltage, while the variation of the top or bottom interface Schottky barriers, because of the presence of the polarization charge near the top or bottom interface, have a indirect and subordinate influence on the photocurrent.

  16. Lift-off PMN-PT Thick Film for High Frequency Ultrasonic Biomicroscopy.

    Science.gov (United States)

    Zhu, Benpeng; Han, Jiangxue; Shi, Jing; Shung, K Krik; Wei, Q; Huang, Yuhong; Kosec, M; Zhou, Qifa

    2010-10-01

    Piezoelectric 0.65Pb(Mg(1/3)Nb(2/3))O(3)-0.35PbTiO(3) (PMN-35PT) thick film with a thickness of approximately 12 µm has been deposited on the platinum buffered Si substrate via a sol-gel composite method. The separation of the film from the substrate was achieved using a wet chemical method. The lifted-off PMN-35PT thick film exhibited good dielectric and ferroelectric properties. At 1 kHz, the dielectric constant and the dielectric loss were 3,326 and 0.037, respectively, while the remnant polarization was 30.0 µC/cm(2). A high frequency single element acoustic transducer fabricated with this film showed a bandwidth at -6 dB of 63.6% at 110 MHz.

  17. Controlling the alloy composition of PtNi nanocrystals using solid-state dewetting of bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Okkyun; Oh, Se An; Lee, Ji Yeon; Ha, Sung Soo; Kim, Jae Myung; Choi, Jung Won; Kim, Jin-Woo [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of); Kang, Hyon Chol [Department of Materials and Science Engineering, Chosun University, Gwangju 61542 (Korea, Republic of); Noh, Do Young, E-mail: dynoh@gist.ac.kr [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of)

    2016-05-15

    We demonstrate that solid-state dewetting of bilayer films is an effective way for obtaining bimetallic alloy nanocrystals of controlled composition. When a Pt–Ni bilayer film were annealed near 700 °C, Pt and Ni atoms inter-diffused to form a PtNi bimetallic alloy film. Upon annealing at higher temperatures, the bilayer films transformed into <111> oriented PtNi alloy nanocrystals in small-rhombicuboctahedron shape through solid-state dewetting process. The Pt content of the nanocrystals and the alloy films, estimated by applying the Vegard's law to the relaxed lattice constant, was closely related to the thickness of each layer in the as-grown bilayer films which can be readily controlled during bilayer deposition. - Highlights: • Composition control of PtNi nanoparticles using solid state dewetting is proposed. • PtNi alloy composition was controlled by thickness ratio of Pt–Ni bilayer films. • PtNi alloy nanocrystals were obtained in small-rhombicuboctahedron shape.

  18. Irreversible modification of magnetic properties of Pt/Co/Pt ultrathin films by femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Kisielewski, J., E-mail: jankis@uwb.edu.pl [Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525AJ Nijmegen (Netherlands); Laboratory of Magnetism, University of Białystok, Lipowa 41, 15-424 Białystok (Poland); Dobrogowski, W.; Kurant, Z.; Stupakiewicz, A.; Tekielak, M.; Maziewski, A. [Laboratory of Magnetism, University of Białystok, Lipowa 41, 15-424 Białystok (Poland); Kirilyuk, A.; Kimel, A.; Rasing, Th. [Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525AJ Nijmegen (Netherlands); Baczewski, L. T.; Wawro, A. [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland); Balin, K.; Szade, J. [A. Chełkowski Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland)

    2014-02-07

    Annealing ultrathin Pt/Co/Pt films with single femtosecond laser pulses leads to irreversible spin-reorientation transitions and an amplification of the magneto-optical Kerr rotation. The effect was studied as a function of the Co thickness and the pulse fluence, revealing two-dimensional diagrams of magnetic properties. While increasing the fluence, the creation of two branches of the out-of-plane magnetization state was found.

  19. Growth, structure and magnetic properties of magnetron sputtered FePt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cantelli, Valentina

    2010-07-01

    The L1{sub 0} FePt phase belongs to the most promising hard ferromagnetic materials for high density recording media. The main challenges for thin FePt films are: (i) to lower the process temperature for the transition from the soft magnetic A1 to the hard magnetic L1{sub 0} phase, (ii) to realize c-axes preferential oriented layers independently from the substrate nature and (iii) to control layer morphology supporting the formation of FePt-L1{sub 0} selforganized isolated nanoislands towards an increase of the signal-to-noise ratio. In this study, dc magnetron sputtered FePt thin films on amorphous substrates were investigated. The work is focused on the correlation between structural and magnetic properties with respect to the influence of deposition parameters like growth mode (cosputtering vs. layer - by - layer) and the variation of the deposition gas (Ar, Xe) or pressure (0.3-3 Pa). In low-pressure Ar discharges, high energetic particle impacts support vacancies formation during layer growth lowering the phase transition temperature to (320{+-}20) C. By reducing the particle kinetic energy in Xe discharges, highly (001) preferential oriented L1{sub 0}-FePt films were obtained on a-SiO{sub 2} after vacuum annealing. L1{sub 0}-FePt nano-island formation was supported by the introduction of an Ag matrix, or by random ballistic aggregation and atomic self shadowing realized by FePt depositions at very high pressure (3 Pa). The high coercivity (1.5 T) of granular, magnetic isotropic FePt layers, deposited in Ar discharges, was measured with SQUID magnetometer hysteresis loops. For non-granular films with (001) preferential orientation the coercivity decreased (0.6 T) together with an enhancement of the out-of- plane anisotropy. Nanoislands show a coercive field close to the values obtained for granular layers but exhibit an in-plane easy axis due to shape anisotropy effects. An extensive study with different synchrotron X-ray scattering techniques, mainly

  20. Magnetic anisotropy and chemical long-range order in epitaxial ferrimagnetic CrPt sub 3 films

    CERN Document Server

    Maret, M; Köhler, J; Poinsot, R; Ulhaq-Bouillet, C; Tonnerre, J M; Berar, J F; Bucher, E

    2000-01-01

    Thin films of CrPt sub 3 were prepared by molecular beam epitaxy on both Al sub 2 O sub 3 (0 0 0 1) and MgO(0 0 1) substrates, either directly by co-deposition of Cr and Pt at high temperatures or after in situ annealing of superlattices [Cr(2 A)/Pt(7 A)]. In situ RHEED observations and X-ray diffraction measurements have allowed us to check the single-crystal quality of CrPt sub 3 films and to determine the degree of L1 sub 2 -type long-range order (LRO). In films co-deposited between 850 deg. C and 950 deg. C a nearly perfect LRO has been observed. As in bulk alloys, such ordering yields a ferrimagnetic order, while the disordered films are non-magnetic. In contrast with the ferromagnetic L1 sub 2 -type ordered CoPt sub 3 (1 1 1) films, the ferrimagnetic CrPt sub 3 (1 1 1) films exhibit perpendicular magnetic anisotropy with quality factors, K sub u /K sub d , as large as 5 and large coercivities around 450 kA/m. Such anisotropy could be related to the arrangement of Cr atoms, which owing to their large mag...

  1. Annealing effects of chemically synthesized FePt nanocrystal films

    Science.gov (United States)

    Hyun, Changbae; Lee, Doh C.

    2005-03-01

    Chemically synthesized FePt nanocrystals can exhibit room temperature ferromagnetism after being annealed at temperatures above ˜500^oC[1]. The thermal annealing changes the crystal structure from face-centered cubic to the hard magnetic face-centered tetragonal phase. In thick nanocrystal films, the coercivity can be quite large, however, the coercivity of thin films has been found to decrease significantly with decreasing thickness, even losing the room temperature ferromagnetism in some cases[2]. In order to help determine how the microscopic magnetic structure in these thin films evolves with film thickness, we studied using magnetic force microscopy (MFM), under external applied fields, films consisting of 4 to 15 nanocrystal monolayers. We cast smooth films of 4 nm diameter FePt nanocrystals and annealed them at temperatures ranging from 400 to 650^oC, acquiring MFM images as a function of annealing temperature. Thin FePt films showed lower coercivity than thick films. To help interpret the MFM images, complementary magnetic and structural data was obtained using SQUID magnetometry, x-ray diffraction, and transmission electron microscopy (TEM). [1] S. Sun et al., Science 287, 1989 (2000). [2] G. A. Held et al., Journal of Applied Physics 95, 1481 (2004)

  2. Magnetic anisotropy and chemical long-range order in epitaxial ferrimagnetic CrPt{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Maret, M. E-mail: mireille.maret@uni-konstanz.de; Albrecht, M.; Koehler, J.; Poinsot, R.; Ulhaq-Bouillet, C.; Tonnerre, J.M.; Berar, J.F.; Bucher, E

    2000-08-01

    Thin films of CrPt{sub 3} were prepared by molecular beam epitaxy on both Al{sub 2}O{sub 3}(0 0 0 1) and MgO(0 0 1) substrates, either directly by co-deposition of Cr and Pt at high temperatures or after in situ annealing of superlattices [Cr(2 A)/Pt(7 A)]. In situ RHEED observations and X-ray diffraction measurements have allowed us to check the single-crystal quality of CrPt{sub 3} films and to determine the degree of L1{sub 2}-type long-range order (LRO). In films co-deposited between 850 deg. C and 950 deg. C a nearly perfect LRO has been observed. As in bulk alloys, such ordering yields a ferrimagnetic order, while the disordered films are non-magnetic. In contrast with the ferromagnetic L1{sub 2}-type ordered CoPt{sub 3}(1 1 1) films, the ferrimagnetic CrPt{sub 3}(1 1 1) films exhibit perpendicular magnetic anisotropy with quality factors, K{sub u}/K{sub d}, as large as 5 and large coercivities around 450 kA/m. Such anisotropy could be related to the arrangement of Cr atoms, which owing to their large magnetic moment, oppositely directed to the small Pt moment, drive the magnetization. Since the six Cr nearest neighbours around a Cr atom are along the <0 0 1> directions, making an angle of 54.74 deg. with the [1 1 1] growth direction, the overlap of their electron distribution favors an easy axis of magnetization normal to the film plane. This idea is supported by the absence of magnetic anisotropy in ferrimagnetic CrPt{sub 3}(0 0 1) films.

  3. CoPt alloy films on SiO{sub 2} nanoparticle arrays

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Denys; Schatz, Guenter [University of Konstanz (Germany). Department of Physics; Bermudez, Esteban; Schmidt, Oliver G. [IFW, Dresden (Germany); Brombacher, Christoph; Albrecht, Manfred [Chemnitz University of Technology (Germany). Institute of Physics; Liscio, Fabiola; Maret, Mireille [ENSEEG, Saint Martin d' Heres (France)

    2008-07-01

    Combining self-assembled SiO{sub 2} nanoparticle arrays with magnetic film deposited onto the particles, enables an elegant possibility to create magnetic nanostructure arrays with defined magnetic properties. In this regard, materials such as CoPt alloy are of particular interest due to their large magnetic anisotropy required for thermal stability in the high density magnetic recording applications. In order to induce high perpendicular magnetic anisotropy in CoPt alloys, the L1{sub 0} phase with (001) texturing is required. For this purpose, a 10 nm thick MgO(001) seed layer was introduced. Results on planar amorphous SiO{sub 2} substrates reveal an uniaxial out-of-plane magnetic anisotropy and saturation magnetization for the CoPt alloy grown at 450 C of about 5x10{sup 5} J/m{sup 3} and 800 kA/m. These properties were transfered to CoPt alloy deposited onto arrays of SiO{sub 2} particles with diameters down to 50 nm. The formed CoPt nanocaps are in a magnetic single domain state with a large out-of-plane coercivity, which increases with decreasing particle size. In this presentation, the structural and magnetic properties are discussed and compared to the planar film.

  4. Exploring the potential of remote plasma sputtering for the production of L10 ordered FePt thin films

    Science.gov (United States)

    Zygridou, S.; Barton, C. W.; Nutter, P. W.; Thomson, T.

    2017-07-01

    Lowering the temperature at which the desirable L10 phase forms in FePt thin films is a key requirement in the development of next generation high-density data storage media and spintronic devices. Remote plasma sputtering offers a higher degree of control over the sputtering parameters, allowing the properties of films to be tailored, and potentially can affect the ordering kinetics of the L10 phase of FePt. Here, we report a comprehensive study of FePt thin films deposited under a range of temperatures and sputtering conditions. X-ray diffraction and magnetometry investigations show that whilst FePt thin films ordered in the L10 phase with high perpendicular anisotropy can be produced using this technique, there is no significant reduction in the required ordering temperature compared with films produced using conventional DC sputtering. Optimally ordered L10 FePt films were fabricated when the film was deposited at a substrate temperature of 200 °C, followed by post annealing at 750 °C.

  5. Enhanced coercivity of HCP Co–Pt alloy thin films on a glass substrate at room temperature for patterned media

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.S. [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China); Sun, An-Cheng, E-mail: acsun@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China); Lee, H.Y. [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 300, Taiwan (China); Department of Applied Science, National Hsinchu University of Education, Hsinchu 300, Taiwan (China); Lu, Hsi-Chuan; Wang, Sea-Fue [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Sharma, Puneet [School of Physics and Materials Science, Thapar University, Patiala (India)

    2015-10-01

    High coercivity (H{sub c}) Co-rich type Co–Pt alloy thin films with a columnar grain structure were deposited at room temperature (RT) by magnetron sputtering. Films with a thickness (t) of up to 10 nm had a FCC structure and exhibited soft magnetic properties. When t>25 nm, the magnetic anisotropy changed from in-plane to isotropic. H{sub c} was also enhanced with increasing t and found to be maximum at t=50 nm. The in-plane and out-of-plane H{sub c} of the film was 2.2 and 2.7 kOe, respectively. Further increasing t led to a slight decrease in H{sub c}. Microstructure and phase structure studies revealed columnar Co–Pt grains with a uniform lateral size grown on a 7 nm initial layer. Films with t>25 nm showed a HCP phase, due to the internal stress and volume effect. The microstructural details responsible for the enhanced RT magnetic properties of the HCP Co–Pt alloy thin films were investigated by TEM. - Highlights: • Deposited Co–Pt alloy thin films on glass substrate at room temperature. • High out-of-plane coercivity of Co-rich type Co–Pt thin film at thinner thickness. • Columnar structure contributed out-of-plane coercivity.

  6. Atomic Structure Control of Silica Thin Films on Pt(111)

    KAUST Repository

    Crampton, Andrew S

    2015-05-27

    Metal oxide thin films grown on metal single crystals are commonly used to model heterogeneous catalyst supports. The structure and properties of thin silicon dioxide films grown on metal single crystals have only recently been thoroughly characterized and their spectral properties well established. We report the successful growth of a three- dimensional, vitreous silicon dioxide thin film on the Pt(111) surface and reproduce the closed bilayer structure previously reported. The confirmation of the three dimensional nature of the film is unequivocally shown by the infrared absorption band at 1252 cm−1. Temperature programmed desorption was used to show that this three-dimensional thin film covers the Pt(111) surface to such an extent that its application as a catalyst support for clusters/nanoparticles is possible. The growth of a three-dimensional film was seen to be directly correlated with the amount of oxygen present on the surface after the silicon evaporation process. This excess of oxygen is tentatively attributed to atomic oxygen being generated in the evaporator. The identification of atomic oxygen as a necessary building block for the formation of a three-dimensional thin film opens up new possibilities for thin film growth on metal supports, whereby simply changing the type of oxygen enables thin films with different atomic structures to be synthesized. This is a novel approach to tune the synthesis parameters of thin films to grow a specific structure and expands the options for modeling common amorphous silica supports under ultra high vacuum conditions.

  7. Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes

    Directory of Open Access Journals (Sweden)

    Cui Yan

    2014-01-01

    Full Text Available Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47O3 (PZT thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films.

  8. Modification of Pt/Co/Pt film properties by ion irradiation

    Science.gov (United States)

    Avchaciov, K. A.; Ren, W.; Djurabekova, F.; Nordlund, K.; Sveklo, I.; Maziewski, A.

    2015-09-01

    We studied the structural modifications of a Pt/Co/Pt trilayer epitaxial film under Ga+ 30-keV ion irradiation by means of classical molecular dynamics and Monte Carlo simulations. The semiclassical tight-binding second-moment approximation potential was adjusted to reproduce the enthalpies of formation, the lattice constants, and the order-disorder transition temperatures for Co-Pt alloys. We found that during irradiation, the sandwich-type Pt(fcc)/Co(hcp)/Pt(fcc) film structure underwent a transition to the new solid solution α -Co /Pt (fcc ) phase. Our analysis of the short-range order indicates the formation, within a nanosecond time scale, of a homogeneous chemically disordered solution. The longer time-scale simulations employing a Monte Carlo algorithm demonstrated that the transition from the disordered phase to the ordered L 10 and L 12 phases was also possible but not significant for the changes in perpendicular magnetic anisotropy (PMA) observed experimentally. The strain analysis showed that the Co layer was under tensile strain in the lateral direction at the fluences of 1.5 ×1014-3.5 ×1014ionscm -2 ; this range of fluences corresponds to the appearance of PMA. This strain was induced in the initially relaxed hcp Co layer due to its partial transformation to the fcc phase and to the influence of atomic layers with larger lattice constants at upper/lower interfaces.

  9. Influence of Bath Composition on Magnetic Properties of Electrodeposited Co-Pt-W Thin Films

    Institute of Scientific and Technical Information of China (English)

    GE Hong-liang; WEI Guo-ying; WU Qiong; ZHOU Qiao-ying; WANG Xin-yan

    2007-01-01

    Effect of bath composition ([Co2+]/[PtⅣ] and [WO2-4], [cit-]) and pH on the magnetic properties of electrodeposited Co-Pt-W thin films has been investigated. Electrodeposited Co-Pt-W thin films exhibited strong perpendicular magnetic anisotropy when the ratio of [Co2+] to [PtⅣ] was 10; cathode current efficiency and perpendicular magnetic anisotropy showed little variations when [WO2-4] was lower than 0.1 mol/L, but perpendicular magnetic anisotropy had strengthened when [WO2-4] was over 0.1 mol/L, which could be explained by the fact that the hydrogen evolution could produce pores as magnetic domain pinnings; citrate as complexing reagent can promote the polarization of [Co2+] and [PtⅣ]. As a result, the equilibrium electrode potentials of cobalt and platinum moved to negative direction, which led to the co-deposition of Co, Pt, and W. It was also found out that the as-deposited Co-Pt-W hard magnetic thin films were very homogeneous, smooth, and had the maximum coercivity for the bath pH 8.5 and the concentration of citrate 0.26 mol/L.

  10. (001) textured FePt thin films on spherical SiO{sub 2} nanoparticle template

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph; Schubert, Christian; Teichgraeber, Andreas; Hietschold, Michael; Albrecht, Manfred [Institute of Physics, TU Chemnitz, Chemnitz (Germany); Romer-Urban, Sara [Nanoscale Materials Science, Empa, Duebendorf (Switzerland); Maret, Mireille [Laboratoire de Thermodynamique et Physico-Chimie Metallurgiques, ENSEEG, Saint Martin d' Heres (France); Makarov, Denys [Department of Physics, University of Konstanz, Konstanz (Germany)

    2009-07-01

    Due to its high magnetocrystalline anisotropy and excellent corrosion resistance, FePt is considered one of the most promising candidates for future magnetic data storage devices. In this study, densely-packed arrays of SiO{sub 2} nanoparticles have been used as a template to create regular FePt nanostructures suitable for application as patterned media. The sputter deposited FePt film displays a chemically disordered fcc phase. Postannealing in a commercial RTA setup yields both a high ordering parameter and the desired (001) texture as shown by XRD and TEM. The heating rate, heating time and heating temperature have been optimized on planar SiO{sub 2} substrates, obtaining perpendicular magnetic anisotropy and coercivities of up to 2 T. Furthermore, the FePt films exhibit a strong dewetting behavior on both planar substrates and spherical nanoparticles. By tuning the thickness of the FePt layer, the characteristic length scales of the dewetting process can be controlled. This was used to create isolated FePt nanostructures on SiO{sub 2} particle arrays with periodicities down to 50 nm.

  11. Electric field modification of magnetotransport in Ni thin films on (011) PMN-PT piezosubstrates

    Science.gov (United States)

    Tkach, Alexander; Kehlberger, Andreas; Büttner, Felix; Jakob, Gerhard; Eisebitt, Stefan; Kläui, Mathias

    2015-02-01

    This study reports the magnetotransport and magnetic properties of 20 nm-thick polycrystalline Ni films deposited by magnetron sputtering on unpoled piezoelectric (011) [PbMg1/3Nb2/3O3]0.68-[PbTiO3]0.32 (PMN-PT) substrates. The longitudinal magnetoresistance (MR) of the Ni films on (011) PMN-PT, measured at room temperature in the magnetic field range of -0.3 T PMN-PT substrate, which results in a transfer of strain to the Ni film, the MR value decreases by factor of 20 for the current along [100] of PMN-PT and slightly increases for the [ 01 1 ¯ ] current direction. Simultaneously, a strong increase (decrease) in the field value, where the MR saturates, is observed for the [ 01 1 ¯ ] ([100]) current direction. The anisotropic magnetoresistance is also strongly affected by the remanent strain induced by the electric field pulses applied to the PMN-PT in the non-linear regime revealing a large (132 mT) magnetic anisotropy field. Applying a critical electric field of 2.4 kV/cm, the anisotropy field value changes back to the original value, opening a path to voltage-tuned magnetic field sensor or storage devices. This strain mediated voltage control of the MR and its dependence on the crystallographic direction is correlated with the results of magnetization reversal measurements.

  12. Domain wall pinning on strain relaxation defects in FePt(001)/Pt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Attane, J. P.; Samson, Y.; Marty, A.; Halley, D.; Beigne, C.

    2001-08-06

    Thin FePt (001) films, grown by molecular-beam epitaxy on Pt(001), exhibit a very large perpendicular magnetic anisotropy (K{sub u}=5 x 10{sup 6}Jm{sup -3}) and a 100% magnetic remanence in perpendicular field. The lattice misfit between FePt and Pt (1.5%) relaxes through the pileup of a/6 <112> partial dislocations along {l_brace}111{r_brace} planes, leading to the formation of microtwins. Atomic force microscopy images demonstrate that this process induces a spontaneous rectangular nanostructuration of the sample, while magnetic force microscopy shows that the microtwins act as pinning sites for the magnetic walls. This leads to square magnetic domains and explains the large coercivity associated with the domain wall propagation. {copyright} 2001 American Institute of Physics.

  13. Domain wall pinning on strain relaxation defects in FePt(001)/Pt thin films

    Science.gov (United States)

    Attané, J. P.; Samson, Y.; Marty, A.; Halley, D.; Beigné, C.

    2001-08-01

    Thin FePt (001) films, grown by molecular-beam epitaxy on Pt(001), exhibit a very large perpendicular magnetic anisotropy (Ku=5×106J m-3) and a 100% magnetic remanence in perpendicular field. The lattice misfit between FePt and Pt (1.5%) relaxes through the pileup of a/6 partial dislocations along {111} planes, leading to the formation of microtwins. Atomic force microscopy images demonstrate that this process induces a spontaneous rectangular nanostructuration of the sample, while magnetic force microscopy shows that the microtwins act as pinning sites for the magnetic walls. This leads to square magnetic domains and explains the large coercivity associated with the domain wall propagation.

  14. Rhombohedral AlPt films formed by self-propagating, high temperature synthesis.

    Energy Technology Data Exchange (ETDEWEB)

    Adams, David Price; Rodriguez, Mark Andrew; Kotula, Paul Gabriel

    2005-11-01

    High-purity AlPt thin films prepared by self-propagating, high temperature combustion synthesis show evidence for a new rhombohedral phase. Sputter deposited Al/Pt multilayers of various designs are reacted at different rates in air and in vacuum, and each form a new trigonal/hexagonal aluminide phase with unit cell parameters a = 15.571(8) {angstrom}, c = 5.304(1) {angstrom}, space group R-3 (148), and Z, the number of formula units within a unit cell, = 39. The lattice is isostructural to that of the AlPd R-3 lattice as reported by Matkovic and Schubert (Matkovic, 1977). Reacted films have a random in-plane crystallographic texture, a modest out-of-plane (001) texture, and equiaxed grains with dimensions on the order of film thickness.

  15. Tailoring Curie temperature and magnetic anisotropy in ultrathin Pt/Co/Pt films

    Directory of Open Access Journals (Sweden)

    Vineeth Mohanan Parakkat

    2016-05-01

    Full Text Available The dependence of perpendicular magnetization and Curie temperature (Tc of Pt/Co/Pt thin films on the thicknesses of Pt seed (Pts and presence of Ta buffer layer has been investigated in this work. Pt and Co thicknesses were varied between 2 to 8 nm and 0.35 to 1.31 nm (across the spin reorientation transition thickness respectively and the Tc was measured using SQUID magnetometer. We have observed a systematic dependence of Tc on the thickness of Pts. For 8nm thickness of Pts the Co layer of 0.35nm showed ferromagnetism with perpendicular anisotropy at room temperature. As the thickness of the Pts was decreased to 2nm, the Tc went down below 250K. XRD data indicated polycrystalline growth of Pts on SiO2. On the contrary Ta buffer layer promoted the growth of Pt(111. As a consequence Ta(5nm/Pt(3nm/Co(0.35nm/Pt(2nm had much higher Tc (above 300K with perpendicular anisotropy when compared to the same stack without the Ta layer. Thus we could tune the ferromagnetic Tc and anisotropy by varying the Pts thickness and also by introducing Ta buffer layer. We attribute these observations to the micro-structural evolution of Pts layer which hosts the Co layer.

  16. Sputter deposited Terfenol-D thin films for multiferroic applications

    Directory of Open Access Journals (Sweden)

    K. P. Mohanchandra

    2015-09-01

    Full Text Available In this paper, we study the sputter deposition and crystallization process to produce high quality Terfenol-D thin film (100 nm with surface roughness below 1.5 nm. The Terfenol-D thin film was produced using DC magnetron sputtering technique with various sputtering parameters and two different crystallization methods, i.e. substrate heating and post-annealing. Several characterization techniques including WDS, XRD, TEM, AFM, SQUID and MOKE were used to determine the physical and magnetic properties of the Terfenol-D films. TEM studies reveal that the film deposited on the heated substrate has large grains grown along the film thickness producing undesirable surface roughness while the film crystallized by post-annealing method shows uniformly distributed small grains producing a smooth surface. The Terfenol-D film was also deposited onto (011 cut PMN-PT single crystal substrate. With the application of an electric field the film exhibited a 1553 Oe change in coercivity with an estimated saturation magnetostriction of λs = 910 x 10−6.

  17. Sputter deposited Terfenol-D thin films for multiferroic applications

    Science.gov (United States)

    Mohanchandra, K. P.; Prikhodko, S. V.; Wetzlar, K. P.; Sun, W. Y.; Nordeen, P.; Carman, G. P.

    2015-09-01

    In this paper, we study the sputter deposition and crystallization process to produce high quality Terfenol-D thin film (100 nm) with surface roughness below 1.5 nm. The Terfenol-D thin film was produced using DC magnetron sputtering technique with various sputtering parameters and two different crystallization methods, i.e. substrate heating and post-annealing. Several characterization techniques including WDS, XRD, TEM, AFM, SQUID and MOKE were used to determine the physical and magnetic properties of the Terfenol-D films. TEM studies reveal that the film deposited on the heated substrate has large grains grown along the film thickness producing undesirable surface roughness while the film crystallized by post-annealing method shows uniformly distributed small grains producing a smooth surface. The Terfenol-D film was also deposited onto (011) cut PMN-PT single crystal substrate. With the application of an electric field the film exhibited a 1553 Oe change in coercivity with an estimated saturation magnetostriction of λs = 910 x 10-6.

  18. Growth of a Pt film on non-reduced ceria: a density functional theory study.

    Science.gov (United States)

    Loffreda, David; Delbecq, Françoise

    2012-01-28

    The growth of platinum on non-reduced CeO(2) (111) surface is studied by means of calculations based on the density functional theory. Particles of increasing size are formed on the oxide surface by incorporating the platinum atoms one by one until multilayer films are obtained. The main conclusion is that platinum atoms tend to maximize the number of metallic bonds and to approach the situation of the bulk, hence preferring films to particles, particles to isolated atoms, and a three-dimensional growth to a two-dimensional one. The supported particles and the films exhibit a contraction of the Pt-Pt distances, with respect to those of the Pt bulk, in order to match the ceria lattice. The density of states projected on the film surface platinum atoms shows important differences in shape and energy (lower d-band center) compared to the Pt(111) reference surface, which could be the major reason for the observed changes in catalytic reactivity when deposited particles are compared with single crystal surfaces.

  19. Effects of Ag addition on FePt L1{sub 0} ordering transition: A direct observation of ordering transition and Ag segregation in FePtAg alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Yu, Youxing, E-mail: yuyouxing@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Gao, Tenghua [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1, Oh-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2015-12-21

    FePt and (FePt){sub 91.2}Ag{sub 8.8} alloy films were deposited by magnetron sputtering. The average coercivity of (FePt){sub 91.2}Ag{sub 8.8} films reaches 8.51 × 10{sup 5} A/m, which is 0.63 × 10{sup 5} A/m higher than that of the corresponding FePt films. Ag addition effectively promotes the FePt L1{sub 0} ordering transition at a relatively low annealing temperature of 400 °C. The promotion mechanism was investigated by using in situ high-resolution transmission electron microscopy (HRTEM) and ex situ X-ray absorption fine structure (XAFS). The concurrence of ordering transition and Ag segregation in FePtAg alloy films was first observed by using in situ heating HRTEM. The time-resolved evolution reveals more details on the role of Ag addition in FePt low-temperature ordering. Ex situ XAFS results further confirm that Ag replaces Fe sites in the as-deposited films and segregates from FePt-Ag solid solution phase through annealing at elevated temperatures. The segregation of Ag atoms leaves vacancies in the grain. The vacancy formation is believed to accelerate the diffusion of Fe and Pt atoms, which is critical for the L1{sub 0} ordering transition.

  20. Deposition temperature mediated tunable tilt angle magnetization in Co–Pt/Ni{sub 81}Fe{sub 19} exchange springs

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, P. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Tsai, C.L. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Lee, C.-M. [Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou 64002, Taiwan (China)

    2015-05-01

    In this study, we investigate the effect of deposition temperature of Co–Pt fixed layer, T{sub d,CoPt} (150, 250 and 350 °C) on the tilt angle magnetization (θ{sub M}) of Ni{sub 81}Fe{sub 19}-layer grown at room temperature (RT) and at different thicknesses (t{sub NiFe}=0, 1.0, 2.5 and 4.0 nm) in Co–Pt(T{sub d,CoPt})/NiFe(t{sub NiFe}) exchange springs. The magnetic studies demonstrated a strong perpendicular magnetic anisotropy (PMA) for the equi-compositional ordered Co–Pt layer grown on glass substrate using the film sequence: Ta(20 nm)/Pt(20 nm)/CoPt(5 nm), regardless of T{sub d,CoPt}. The PMA can be retained with the addition of a 4-nm NiFe layer on the top when T{sub d,CoPt}≥250 °C. In contrast, relatively a thin layer of Ni–Fe (2.5 nm) can destroy the perpendicular exchange-spring behavior if the Co–Pt layer is deposited at RT. Using 3-D micromagnetic simulation, the interfacial exchange coupling strength (A{sub ij}) between the Co–Pt and NiFe-layers was estimated and the A{sub ij} value is found to increase rapidly when T{sub d,CoPt} is increased from RT to 300 °C. Besides, the magnetization tilted angle (θ{sub M}) of NiFe can be easily tuned from completely out-of-plane to almost 60° when t{sub NiFe}=4.0 nm. Through this study, it is demonstrated that the θ{sub M} of NiFe-layer can be tuned by not only altering the t{sub NiFe}; but also by varying the T{sub d,CoPt}. - Highlights: • Equi-compositional ordered 5-nm thick Co–Pt with strong PMA was grown on glass. • The ordered Co–Pt and Ni{sub 81}Fe{sub 19} layers were utilized for OOP and IP-anisotropies. • Tunable tilt angle magnetization was investigated by varying T{sub d,CoPt}. • Using micromagnetic simulation, interfacial exchange coupling strength was deduced. • Deposition temperature mediated θ{sub M} in Co–Pt/NiFe provides a new scope for STO.

  1. MAGNETIC EXCHANGE-COUPLING IN CoPt/Co BILAYER THIN FILMS

    Energy Technology Data Exchange (ETDEWEB)

    KIM,J.; BARMAK,K.; LEWIS,L.H.; CREW,D.C.; WELCH,D.O.

    1999-04-05

    Thin film CoPt/Co bilayers have been prepared as a model system to investigate the relationship between microstructure and exchange coupling in two-phase hard/soft composite magnets. CoPt films, with a thickness of 25 nm, were sputter-deposited from a nearly equiatomic alloy target onto oxidized Si wafers. The films were subsequently annealed at 700 C and fully transformed from the FCC phase to the magnetically hard, ordered L1{sub 0} phase. The coercivity of the films increased rapidly with annealing time until it reached a plateau at approximately 9.5 kOe. Fully-ordered CoPt films were then used as substrates for deposition of Co layers, with thicknesses in the range of 2.8--225 nm, in order to produce the hard/soft composite bilayers. As predicted by theory, the magnetic coherency between the soft Co phase and the hard, ordered CoPt phase decreased as the thickness of the soft phase increased. This decrease in coupling was clearly seen in the magnetic hysteresis loops of the bilayers. At small thicknesses of Co (a few nanometers), the shape of the loop was one of a uniform material showing no indication of the presence of two phases with extremely different coercivities. At larger Co thicknesses, constricted loops, i.e., ones showing the presence of a mixture of two ferromagnetic phases of different hardnesses, were obtained. The magnetic exchange present in the bilayer samples was qualitatively analyzed using magnetic recoil curves and the dependence of exchange coupling on the soft phase dimension in the bilayer hard/soft composite magnet films is discussed.

  2. Deposition temperature mediated tunable tilt angle magnetization in Co-Pt/Ni81Fe19 exchange springs

    Science.gov (United States)

    Saravanan, P.; Hsu, Jen-Hwa; Tsai, C. L.; Lee, C.-M.

    2015-05-01

    In this study, we investigate the effect of deposition temperature of Co-Pt fixed layer, Td,CoPt (150, 250 and 350 °C) on the tilt angle magnetization (θM) of Ni81Fe19-layer grown at room temperature (RT) and at different thicknesses (tNiFe=0, 1.0, 2.5 and 4.0 nm) in Co-Pt(Td,CoPt)/NiFe(tNiFe) exchange springs. The magnetic studies demonstrated a strong perpendicular magnetic anisotropy (PMA) for the equi-compositional ordered Co-Pt layer grown on glass substrate using the film sequence: Ta(20 nm)/Pt(20 nm)/CoPt(5 nm), regardless of Td,CoPt. The PMA can be retained with the addition of a 4-nm NiFe layer on the top when Td,CoPt≥250 °C. In contrast, relatively a thin layer of Ni-Fe (2.5 nm) can destroy the perpendicular exchange-spring behavior if the Co-Pt layer is deposited at RT. Using 3-D micromagnetic simulation, the interfacial exchange coupling strength (Aij) between the Co-Pt and NiFe-layers was estimated and the Aij value is found to increase rapidly when Td,CoPt is increased from RT to 300 °C. Besides, the magnetization tilted angle (θM) of NiFe can be easily tuned from completely out-of-plane to almost 60° when tNiFe=4.0 nm. Through this study, it is demonstrated that the θM of NiFe-layer can be tuned by not only altering the tNiFe; but also by varying the Td,CoPt.

  3. Misfit strain phase diagrams of epitaxial PMN–PT films

    Energy Technology Data Exchange (ETDEWEB)

    Khakpash, N.; Khassaf, H.; Rossetti, G. A. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Alpay, S. P., E-mail: p.alpay@ims.uconn.edu [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-02-23

    Misfit strain–temperature phase diagrams of three compositions of (001) pseudocubic (1 − x)·Pb (Mg{sub l/3}Nb{sub 2/3})O{sub 3} − x·PbTiO{sub 3} (PMN–PT) thin films are computed using a phenomenological model. Two (x = 0.30, 0.42) are located near the morphotropic phase boundary (MPB) of bulk PMN–PT at room temperature (RT) and one (x = 0.70) is located far from the MPB. The results show that it is possible to stabilize an adaptive monoclinic phase over a wide range of misfit strains. At RT, the stability region of this phase is much larger for PMN–PT compared to barium strontium titanate and lead zirconate titanate films.

  4. Misfit strain phase diagrams of epitaxial PMN-PT films

    Science.gov (United States)

    Khakpash, N.; Khassaf, H.; Rossetti, G. A.; Alpay, S. P.

    2015-02-01

    Misfit strain-temperature phase diagrams of three compositions of (001) pseudocubic (1 - x).Pb (Mgl/3Nb2/3)O3 - x.PbTiO3 (PMN-PT) thin films are computed using a phenomenological model. Two (x = 0.30, 0.42) are located near the morphotropic phase boundary (MPB) of bulk PMN-PT at room temperature (RT) and one (x = 0.70) is located far from the MPB. The results show that it is possible to stabilize an adaptive monoclinic phase over a wide range of misfit strains. At RT, the stability region of this phase is much larger for PMN-PT compared to barium strontium titanate and lead zirconate titanate films.

  5. Pulsed laser deposition: Prospects for commercial deposition of epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Muenchausen, R.E.

    1999-03-01

    Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique for the deposition of thin films. The vapor source is induced by the flash evaporation that occurs when a laser pulse of sufficient intensity (about 100 MW/cm{sup 2}) is absorbed by a target. In this paper the author briefly defines pulsed laser deposition, current applications, research directed at gaining a better understanding of the pulsed laser deposition process, and suggests some future directions to enable commercial applications.

  6. (100) MgAl{sub 2}O{sub 4} as a lattice-matched substrate for the epitaxial thin film deposition of the relaxor ferroelectric PMN-PT

    Energy Technology Data Exchange (ETDEWEB)

    Keogh, D.; Maunders, C.; Botton, G.A. [McMaster University, Department of Materials Science and Engineering, Hamilton, Ontario (Canada); McMaster University, Brockhouse Institute for Materials Research, Hamilton, Ontario (Canada); Chen, Z.; Gunawan, L. [McMaster University, Department of Materials Science and Engineering, Hamilton, Ontario (Canada); Hughes, R.A.; Dabkowski, A. [McMaster University, Brockhouse Institute for Materials Research, Hamilton, Ontario (Canada); Marinov, O.; Deen, M.J. [McMaster University, Department of Electrical and Computer Engineering, Hamilton, Ontario, (Canada); Preston, J.S. [McMaster University, Brockhouse Institute for Materials Research, Hamilton, Ontario (Canada); McMaster University, Department of Engineering Physics, Hamilton, Ontario (Canada)

    2010-01-15

    The (100) surface of MgAl{sub 2}O{sub 4} is evaluated as a substrate for the thin film deposition of the relaxor ferroelectric PbMg{sub 1/3}Nb{sub 2/3}O{sub 3}(65%)-PbTiO{sub 3}(35%). With a lattice mismatch of less than 0.5%, this film-substrate combination presents a geometrical template for growth that is far superior to that formed with other commercially available oxide substrates. Films were deposited using the pulsed laser deposition technique and were characterized in terms of their crystallographic, microstructural, and dielectric properties. From a crystallographic perspective the films show excellent cube-on-cube epitaxy, are highly oriented, and show no evidence of the frequently observed parasitic pyrochlore phase. With the exception of a few faceted surface structures, the film's microstructure is single-crystal-like, exhibiting a sharp film-substrate interface, a smooth top surface, and no discernable granularity. The dielectric response shows the frequency-dependent diffuse phase transition characteristic of a relaxor material, but with less frequency dispersion and a smaller maximum in the dielectric constant. Taken together, the results suggest that the (100) MgAl{sub 2}O{sub 4} substrate could prove to be an effective substrate material, not only for the PbMg{sub 1/3}Nb{sub 2/3}O{sub 3}(65%)-PbTiO{sub 3}(35%) system, but also for a number of other important lattice-matched ferroelectric, relaxor, and ferroelectric superlattice systems. (orig.)

  7. Influence of MgO underlayers on the structure and magnetic properties of FePt-C nanogranular films for heat-assisted magnetic recording media

    Directory of Open Access Journals (Sweden)

    T. Shiroyama

    2016-10-01

    Full Text Available In order to optimize the nanogranular structure of FePt-C for heat-assisted magnetic recording media, we investigated the influence of MgO underlayers on the growth of FePt grains in the FePt-C layer. The FePt-C layer was deposited by using the alternating sputtering method, by which FePt and FePt-C layers were alternately deposited. To understand the growth mechanism of the FePt-C layer on the MgO underlayers deposited under various conditions, detailed plan-view and cross sectional transmission electron microscopy observations were made for different film thicknesses. We found that columnar FePt grains grow only when the deposition conditions of the MgO underlayer are optimal. Direct TEM observation of the growth process of the FePt-C layer revealed that the number density of nuclei is sufficient in the initial stage of the film deposition; however, coarsening of the grains after grain impingement causes a substantial decrease in the number density of the FePt grains.

  8. Site-selective Cu deposition on Pt dendrimer-encapsulated nanoparticles: correlation of theory and experiment.

    Science.gov (United States)

    Carino, Emily V; Kim, Hyun You; Henkelman, Graeme; Crooks, Richard M

    2012-03-07

    The voltammetry of Cu underpotential deposition (UPD) onto Pt dendrimer-encapsulated nanoparticles (DENs) containing an average of 147 Pt atoms (Pt(147)) is correlated to density functional theory (DFT) calculations. Specifically, the voltammetric peak positions are in good agreement with the calculated energies for Cu deposition and stripping on the Pt(100) and Pt(111) facets of the DENs. Partial Cu shells on Pt(147) are more stable on the Pt(100) facets, compared to the Pt(111) facets, and therefore, Cu UPD occurs on the 4-fold hollow sites of Pt(100) first. Finally, the structures of Pt DENs having full and partial monolayers of Cu were characterized in situ by X-ray absorption spectroscopy (XAS). The results of XAS studies are also in good agreement with the DFT-optimized models.

  9. Energetic deposition of thin metal films

    CERN Document Server

    Al-Busaidy, M S K

    2001-01-01

    deposited films. The primary aim of this thesis was to study the physical effect of energetic deposition metal thin films. The secondary aim is to enhance the quality of the films produced to a desired quality. Grazing incidence X-ray reflectivity (GIXR) measurements from a high-energy synchrotron radiation source were carried out to study and characterise the samples. Optical Profilers Interferometery, Atomic Force Microscope (AFM), Auger electron spectroscopy (AES), Medium energy ion spectroscopy (MEIS), and the Electron microscope studies were the other main structural characterisation tools used. AI/Fe trilayers, as well as multilayers were deposited using a Nordico planar D.C. magnetron deposition system at different voltage biases and pressures. The films were calibrated and investigated. The relation between energetic deposition variation and structural properties was intensely researched. Energetic deposition refers to the method in which the deposited species possess higher kinetic energy and impact ...

  10. Surface enrichment of Pt in Ga2O3 films grown on liquid Pt/Ga alloys

    Science.gov (United States)

    Grabau, Mathias; Krick Calderón, Sandra; Rietzler, Florian; Niedermaier, Inga; Taccardi, Nicola; Wasserscheid, Peter; Maier, Florian; Steinrück, Hans-Peter; Papp, Christian

    2016-09-01

    The formation of surface Ga2O3 films on liquid samples of Ga, and Pt-Ga alloys with 0.7 and 1.8 at.% Pt was examined using near-ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS). Thickness, composition and growth of the oxide films were deduced as a function of temperature and Pt content of the alloys, in ultra-high vacuum and at oxygen pressures of 3 × 10- 7, 3 × 10- 3 and 1 mbar. We examined oxide layers up to a thickness of 37 Å. Different growth modes were found for oxidation at low and high pressures. The formed Ga2O3 oxide films showed an increased Pt content, while the pristine GaPt alloy showed a surface depletion of Pt at the examined temperatures. Upon growth of Ga2O3 on Pt/Ga alloys a linear increase of Pt content was observed, due to the incorporation of 3.6 at.% Pt in the Ga2O3. The Pt content in Ga2O3, at the examined temperatures and bulk Pt concentrations is found to be independent of pressure, temperature and the nominal Pt content of the metallic alloy.

  11. FePt films on self-assembled SiO2 particle arrays

    Science.gov (United States)

    Makarov, D.; Brombacher, C.; Liscio, F.; Maret, M.; Parlinska, M.; Meier, S.; Kappenberger, P.; Albrecht, M.

    2008-03-01

    Chemically L10 ordered (001) textured FePt thin films with perpendicular magnetic anisotropy can be grown on amorphous planar SiO2 substrate with an underlayer stack of [Pt (3nm )/Cr (50nm)] adopting a [002] orientation when deposited at 350°C. This knowledge of optimum layer stack was transferred to self-assembled SiO2 particle arrays. While 330nm SiO2 particle arrays reveal perpendicular magnetic anisotropy with a remanence of almost one and a coercivity of 370mT, on 160nm particles, the FePt caps show a (111) texturing, leading to the random orientation of the easy axis of the magnetization.

  12. Electrochemical Behaviour of Sputtering Deposited DLC Films

    Institute of Scientific and Technical Information of China (English)

    LIU Erjia; ZENG A,LIU L X

    2003-01-01

    Diamondlike carbon (DLC) films were deposited via magnetron sputtering process. The energetic ion bombardment on the surface of growing film is one of the major parameters that control the atom mobility on the film surface and further the physical and chemical characteristics of the films. In this study, the energy of carbon ions was monitored by changing sputtering power density, and its effect on the electrochemical performance of the films was investigated. For the deposition at a higher sputtering power density, a higher sp3 content in the DLC films was achieved with denser structure and increased film-substrate adhesion. The impedance at the interface of Si substrate/sulfuric acid solution was significantly enhanced, and at the same time higher film resistance, lower capacitance, higher breakdown potential and longer breakdown time were observed, which were related to the significant sp3 content of the DLC films.

  13. Complete wetting of Pt(111) by nanoscale liquid water films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.; Smith, R. Scott; Kay, Bruce D.; Kimmel, Gregory A.

    2016-02-04

    The melting and wetting of nanoscale crystalline ice films on Pt(111) that are transiently heated above the melting point using nanosecond laser pulses are studied with infrared refection absorption spectroscopy (IRAS) and Kr temperature programmed desorption (TPD). The as-grown crystalline ice films consist of isolated nanoscale ice crystallites embedded in a hydrophobic water monolayer. Upon heating above the melting point, these ice crystallites rapidly melt to form nanoscale droplets of liquid water. Rapid cooling of the system to cryogenic temperatures after each laser pulse quenches the water films and allows them to be interrogated with IRAS, Kr TPD and other ultrahigh vacuum surface science techniques. With each successive heat pulse, these liquid drops spread across the surface until it is entirely covered with multilayer water films after several pulses. These results, which show that nanoscale water films completely wet Pt(111), are in contrast to molecular dynamics simulations predicting partial wetting of nanoscale water drops on a hydrophobic water monolayer. The results provide valuable new insights into the wetting characteristics of nanoscale water films on a clean, well-characterized single crystal surface.

  14. Electrochemical Sensor for Oxidation of NO Based on Au-Pt Nanoparticles Self-assembly Film

    Institute of Scientific and Technical Information of China (English)

    XIE,Jia; YU,Zhihui; XIA,Dingguo

    2009-01-01

    Au-Pt bimetallic nanoparticles film used as an efficient electrochemical sensor was prepared by self-assembled Au-Pt bimetallic nanoparticles on a glassy carbon (GC) substrate using thioglycolic acid as a linker. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) showed that the Au-Pt nanoparticles self-assembly film was dense and uniform. Electrochemical experiments revealed that Au-Pt bimetallic nanoparticles film/GC electrode showed high electrocatalytic activity to the oxidation of nitric oxide.

  15. Influence of the polarization anisotropy on the electrocaloric effect in epitaxial PMN-PT thin films

    Science.gov (United States)

    Mietschke, M.; Chekhonin, P.; Molin, C.; Gebhardt, S.; Fähler, S.; Nielsch, K.; Schultz, L.; Hühne, R.

    2016-09-01

    Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) compounds, which are typically used for high performance actuator applications due to their outstanding piezoelectric properties, show, in addition, a pronounced electrocaloric (EC) effect. The study of epitaxial films is a useful tool to analyze the correlation between the microstructure and EC properties in order to optimize the performance of these materials. Therefore, the 0.9PMN-0.1PT films were grown by a pulsed laser deposition on (001) as well as (111) oriented SrTiO3 single crystalline substrates using a La0.7Sr0.3CoO3 buffer as the bottom electrode and additional Au top electrodes. The structural properties determined by a high resolution X-ray and electron microscopy techniques indicated an undisturbed epitaxial growth. The anisotropy of the ferroelectric domain structure was investigated by a vertical and lateral piezoresponse force microscopy showing clear differences between the two orientations. A significant reduction of the thermal hysteresis was observed in the T-dependent polarization measurements for (111) oriented PMN-PT films, whereas the indirectly determined EC properties yield a maximum ΔT of around 15 K at 40 °C for a field of about 400 kV/cm for both film orientations.

  16. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  17. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  18. Electrochemical Behaviour of Sputtering Deposited DLC Films

    Institute of Scientific and Technical Information of China (English)

    LIUErjia; ZENGA; LIULX

    2003-01-01

    Diamondlike carbon (DLC) films were deposited via magnetron sputtering process. The energetic ion hombardment on the surface of growing film is one of the major parameters that control the atom mobility on the flirt1 surface and further the physical and chemical characteristics of the films. In this study, the energy of carbon ions was monitored by changing sputtering powerdensity, and its effect on the electrochemical performance of the films was investigated. For the deposition at a higher sputtering power density, a higher sp3 content in the DLC films was achieved with denser structure and increased film-substrate adhesion. The impedance at the interface of Si substrate/sulfufic acid solution was significantly enhanced, and at the same time higher film resistance, lower capacitance, higher breakdown potential and longer breakdown time were observed, which were related to the significant sp3 content of the DLC films.

  19. In situ spectroscopic ellipsometry during atomic layer deposition of Pt, Ru and Pd

    Science.gov (United States)

    Leick, N.; Weber, J. W.; Mackus, A. J. M.; Weber, M. J.; van de Sanden, M. C. M.; Kessels, W. M. M.

    2016-03-01

    The preparation of ultra-thin platinum-group metal films, such as Pt, Ru and Pd, by atomic layer deposition (ALD) was monitored in situ using spectroscopic ellipsometry in the photon energy range of 0.75-5 eV. The metals’ dielectric function was parametrized using a ‘flexible’ Kramers-Kronig consistent dielectric function because it was able to provide accurate curve shape control over the optical response of the metals. From this dielectric function, it was possible to extract the film thickness values during the ALD process. The important ALD process parameters, such as the nucleation period and growth per cycle of Pt, Ru and Pd could be determined from the thickness evolution. In addition to process parameters, the film resistivity in particular could be extracted from the modeled dielectric function. Spectroscopic ellipsometry thereby revealed itself as a feasible and valuable technique to be used in research and development applications, as well as for process monitoring during ALD.

  20. Effect of Annealing Temperature on the Formation of Silicides and the Surface Morphologies of PtSi Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of annealing temperature on the formation of the PtSi phase, distribution of silicides and the surface morphologies of silicides films is investigated by XPS, AFM. It is shown that the phase sequences of the films change from Pt-Pt2Si-PtSi-Si to Pt+Pt2Si+PtSi-PtSi-Si or Pt+Pt2Si+PtSi-PtSi-Si with an increase of annealing temperature and the reason for the formation of mixed layers is discussed.

  1. The domain structure and polarization retention properties of PT/PZT/PT ferroelectric thin film

    Institute of Scientific and Technical Information of China (English)

    WANG LongHai; Yu Jun; ZHAO SuLing; ZHENG ChaoDuan; WANG YunBo; GAO JunXiong

    2007-01-01

    3The Research & Test Center of Materials, Wuhan University of Technology, Wuhan 430070, ChinaThe highly oriented perovskite-phase PT/PZT/PT ferroelectric thin film was prepared by sol-gel method. The domain structures and polarization retention properties were investigated by scanning force microscopy. The amplitude and phase images of piezoresponse show complex various contrasts of dark, bright and gray.The complex variation of contrast in piezoresponse images results from the perplexing orientation of grains and arrangement of domains in the ferroelectric films.The bright and dark areas in phase images correspond to top-to-bottom and bottom-to-top polarization oriented c-domain, respectively. The gray areas are c-domains with the polarization vector deviating from the direction normal to the film plane. The surface potential images of EFM are bright contrast, which is due to positive charges trapped on the film surface after being polarized by positive voltage. And the brighter contrast is obtained from the higher electric field. The time-dependent surface potential images and line potential profiles show that the potential decays with time. And the decay in the region polarized by higher electric field is faster, especially at 15 min. This indicates that the polarization retention is related to the polarized electric field. Better retention properties may be obtained from a proper polarized electric field.

  2. The domain structure and polarization retention properties of PT/PZT/PT ferroelectric thin film

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The highly oriented perovskite-phase PT/PZT/PT ferroelectric thin film was pre- pared by sol-gel method. The domain structures and polarization retention proper- ties were investigated by scanning force microscopy. The amplitude and phase images of piezoresponse show complex various contrasts of dark, bright and gray. The complex variation of contrast in piezoresponse images results from the per- plexing orientation of grains and arrangement of domains in the ferroelectric films. The bright and dark areas in phase images correspond to top-to-bottom and bot- tom-to-top polarization oriented c-domain, respectively. The gray areas are c-domains with the polarization vector deviating from the direction normal to the film plane. The surface potential images of EFM are bright contrast, which is due to positive charges trapped on the film surface after being polarized by positive volt- age. And the brighter contrast is obtained from the higher electric field. The time-dependent surface potential images and line potential profiles show that the potential decays with time. And the decay in the region polarized by higher electric field is faster, especially at 15 min. This indicates that the polarization retention is related to the polarized electric field. Better retention properties may be obtained from a proper polarized electric field.

  3. Crystallographic origin of perpendicular magnetic anisotropy in CoPt film: polarized x-ray absorption study

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, K [National University of Singapore; Chen, J [National University of Singapore; Liu, T [Oak Ridge National Laboratory (ORNL); Sun, C [Singapore Synchrotron Light Source; Chow, G [National University of Singapore

    2009-01-01

    Crystallographic structure, growth induced miscibility gap and strain in Ta/Co100 xPtx (0 x 43 at%)/Ru/Ta/glass films deposited at ambient temperature were investigated using polarized x-ray absorption spectroscopy to clarify the origin of observed perpendicular magnetic anisotropy (PMA) in Co72Pt28 film. Extended x-ray absorption fine structure spectroscopy data at Co K-edge showed that Co has a similar local atomic environment and averaged interatomic distance in the in-plane and out-of-plane polarization geometries for Co72Pt28, ruling out the contribution of magneto-elastic anisotropy and growth induced structural anisotropy as the origin of PMA. A large PMA in Co72Pt28 film was attributed to the preferred hexagonal close-packed stacking as observed using the x-ray absorption near-edge structure spectroscopy.

  4. Growth of bismuth telluride thin film on Pt by electrochemical atomic layer epitaxy

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Jun-you; GAO Xian-hui; HOU Jie; ZHANG Tong-jun; CUI Kun

    2005-01-01

    An automated thin-layer flow cell electrodeposition system was developed for growing Bi2 Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt,this reductive Te underpotential deposition (UPD)/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4: 3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO2+ reduction excludes the possibility of Bi2 Te3 formation. X-ray photoelectron spectroscopy (XPS) analysis also reveals that the incomplete charge transfer in HTeO2+ occurs in Te direct deposition. The effective way of depositing Bi2 Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). A polycrystalline characteristic was confirmed by XRD. The 2 : 3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about 0.3 - 0.4 μm in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.

  5. Electrochemical promotion of propane oxidation on Pt deposited on a dense β"-Al2O3 ceramic Ag+ conductor

    Directory of Open Access Journals (Sweden)

    Michail eTsampas

    2013-08-01

    Full Text Available A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β"-Al2O3 ceramic Ag+ conductor was developed and evaluated during propane oxidation. It was observed that upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation.

  6. Electrochemical promotion of propane oxidation on Pt deposited on a dense β"-Al2O3 ceramic Ag+ conductor

    Science.gov (United States)

    Tsampas, Michail; Kambolis, Anastasios; Obeid, Emil; Lizarraga, Leonardo; Sapountzi, Foteini; Vernoux, Philippe

    2013-08-01

    A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β"-Al2O3 ceramic Ag+ conductor was developed and evaluated during propane oxidation. It was observed that upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation.

  7. Influence of growth and anneal conditions on the surface roughness of L1{sub 0} Fe{sub 50}Pd{sub x}Pt{sub 50-x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Xin, E-mail: xinjiang@us.ibm.com [Almaden Research Center, IBM Research, 650 Harry Road, San Jose, CA 95120 (United States); Liu Ruisheng; Gao Li; Topuria, Teya; Parkin, Stuart [Almaden Research Center, IBM Research, 650 Harry Road, San Jose, CA 95120 (United States)

    2012-09-15

    We deposit Fe{sub 50}Pd{sub x}Pt{sub 50-x} alloy thin films by magnetron sputtering onto a TiN seed layer. Chemically ordered L1{sub 0} films are obtained which display large perpendicular magnetic anisotropy. We find that the surface roughness of the film depends strongly on the growth and anneal conditions as well as the Pd composition of the film. Smooth films are obtained by deposition above the chemical ordering temperature and by removing Pd from the alloy. - Highlights: Black-Right-Pointing-Pointer FePdPt thin films with strong perpendicular magnetic anisotropy. Black-Right-Pointing-Pointer Strong dependence of surface roughness on Pd composition. Black-Right-Pointing-Pointer FePt roughness strongly influenced by the disorder to order transition process. Black-Right-Pointing-Pointer Reduced FePt film roughness by deposition above the ordering temperature.

  8. Magnetoelectric coupling in multiferroic heterostructure of rf-sputtered Ni-Mn-Ga thin film on PMN-PT

    Energy Technology Data Exchange (ETDEWEB)

    Teferi, M.Y., E-mail: mandefero2002@yahoo.com [Departamento de Fisica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Amaral, V.S.; Lounrenco, A.C.; Das, S. [Departamento de Fisica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Amaral, J.S. [Departamento de Fisica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); IFIMUP-IN and Departamento de Fisica e Astronomia da Faculdade de Ciencias da Universidade do Porto, 4169-007 Porto (Portugal); Karpinsky, D.V. [CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Departamento de Engenharia Ceramica e do Vidro, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Soares, N. [Departamento de Fisica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sobolev, N.A. [Departamento de Fisica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); I3N, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Kholkin, A.L. [CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Departamento de Engenharia Ceramica e do Vidro, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Tavares, P.B. [Centro de Quimica, Universidade de Tras-os-Montes e Alto Douro, 5001-801 Vila Real (Portugal)

    2012-06-15

    In this paper, we report a preparation of multiferroic heterostructure from thin film of Ni-Mn-Ga (NMG) alloy and lead magnesium niobate-lead titanate (PMN-PT) with effective magnetoelectric (ME) coupling between the film as ferromagnetic material and PMN-PT as piezoelectric material. The heterostructure was prepared by relatively low temperature (400 Degree-Sign C) deposition of the film on single crystal of piezoelectric PMN-PT substrate using rf magnetron co-sputtering of Ni{sub 50}Mn{sub 50} and Ni{sub 50}Ga{sub 50} targets. Magnetic measurements by Superconducting Quantum Interference Design (SQIUD) Magnetometer and Vibrating Sample Magnetometer (VSM) on the film revealed that the film is in ferromagnetically ordered martensitic state at room temperature with saturation magnetization of {approx}240 emu/cm{sup 3} and Curie temperature of {approx}337 K. Piezoresponse force microscopy (PFM) measurement done at room temperature on the substrate showed the presence of expected hysteresis loop confirming the stability of the piezoelectric state of the substrate after deposition. Room temperature ME voltage coefficient ({alpha}{sub ME}) of the heterostructure was measured as a function of applied bias dc magnetic field in Longitudinal-Transverse (L-T) ME coupling mode by lock-in technique. A maximum ME coefficient {alpha}{sub ME} of 3.02 mV/cm Oe was measured for multiferroic NMG/PMN-PT heterostructure which demonstrates that there is ME coupling between the film as ferromagnetic material and PMN-PT as piezoelectric material. - Highlights: Black-Right-Pointing-Pointer Multiferroic NMG/PMN-PT heterostructure prepared by depositing NMG alloy thin film on PMN-PT substrate. Black-Right-Pointing-Pointer The film is in ferromagnetically ordered martensite state at room temperature. Black-Right-Pointing-Pointer The substrate maintains its piezoelectric state after deposition. Black-Right-Pointing-Pointer The heterostructure exhibits ME effect with maximum of {alpha}{sub ME

  9. Spontaneous deposition of Ru on Pt (100: morphological and electrochemical studies. Preliminary results of ethanol oxidation at Pt(100/Ru

    Directory of Open Access Journals (Sweden)

    Colle Vinicius D.

    2003-01-01

    Full Text Available In the present work ruthenium was deposited in submonolayer amounts on Pt(100 by spontaneous deposition at several deposition times. The Pt (100/Ru surfaces were analyzed using ex-situ STM to image the deposits characteristic of ruthenium on Pt (100. It was observed the formation of ruthenium islands with diameters between 1.0 and 4.5 nm with bi-atomic thickness in the center of the islands. A homogeneous distribution of the ruthenium islands on the platinum terraces was found, with no preferential deposition on steps or surface defect sites. The ruthenium coverage degree had been calculated by the decrease of charge of the hydrogen adsorption-desorption peaks in the cyclic voltammograms of the Pt(100/Ru electrodes. The Pt(100/Ru electrodes with a ruthenium coverage degree of ca. 0.3 showed a high activity for the ethanol electrooxidation. The electrochemical experimental results support strongly the bifunctional mechanism for the enhanced ethanol oxidation.

  10. Liquid phase deposition of electrochromic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Thomas J.; Rubin, Michael D.

    2000-08-18

    Thin films of titanium, zirconium and nickel oxides were deposited on conductive SnO2:F glass substrates by immersion in aqueous solutions. The films are transparent, conformal, of uniform thickness and appearance, and adhere strongly to the substrates. On electrochemical cycling, TiO2, mixed TiO2-ZrO2, and NiOx films exhibited stable electrochromism with high coloration efficiencies. These nickel oxide films were particularly stable compared with films prepared by other non-vacuum techniques. The method is simple, inexpensive, energy efficient, and readily scalable to larger substrates.

  11. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  12. Perovskite thin films via atomic layer deposition.

    Science.gov (United States)

    Sutherland, Brandon R; Hoogland, Sjoerd; Adachi, Michael M; Kanjanaboos, Pongsakorn; Wong, Chris T O; McDowell, Jeffrey J; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J; Sargent, Edward H

    2015-01-01

    A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3 NH3 PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm(-1) .

  13. Pt/YSZ electrochemical catalysts prepared by electrostatic spray deposition for selective catalytic reduction of NO by C{sub 3}H{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Lintanf, A.; Djurado, E. [Laboratoire d' Electrochimie et de Physico-Chimie des Materiaux et des Interfaces (LEPMI), ENSEEG/INPG/UJF/CNRS Institut National Polytechnique de Grenoble Domaine Universitaire, BP 75, 1130 rue de la Piscine, 38402 St Martin d' Heres Cedex (France); Vernoux, P. [Universite de Lyon, Institut de Recherches sur la Catalyse et l' Environnement de Lyon, UMR 5256, CNRS, Universite Claude Bernard Lyon 1, 2 avenue A. Einstein, 69626 Villeurbanne (France)

    2008-03-15

    Due to the great importance of automotive exhaust gas treatment, the catalytic activity was investigated in selective catalytic reduction of NO by propene on Pt films - with controlled microstructure - deposited on YSZ (8 mol% Y{sub 2}O{sub 3}-doped ZrO{sub 2}) by electrostatic spray deposition. This technique requires low Pt loadings in order to reduce costs and also to achieve high Pt particles dispersion with good reproducibility. This kind of electrochemical catalysts was found to be effective for NO reduction by propene in the presence of oxygen. A dense Pt film was found to be the most suitable. Furthermore, we have demonstrated that these electrochemical catalysts can implement the concept of electrochemical promotion of catalysis (EPOC). (author)

  14. Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2 Film

    OpenAIRE

    Chun He; Mudar Abou Asi; Ya Xiong; Dong Shu; Xiangzhong Li

    2009-01-01

    A series of Pt-TiO2 films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2 films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2 films was evaluated in the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of formic ...

  15. Hard Carbon Films Deposited under Various Atmospheres

    Science.gov (United States)

    Wei, M.-K.; Chen, S.-C.; Wu, T. C.; Lee, Sanboh

    1998-03-01

    Using a carbon target ablated with an XeCl-excimer laser under various gas atmospheres at different pressures, hard carbon was deposited on silicon, iron and tungsten carbide substrates. The hardness, friction coefficient, and wear rate of the film against steel are better than pure substrate material, respectively, so that it has potential to be used as a protective coating for micromechanical elements. The influences of gas pressure, gas atmosphere, and power density of laser irradiation on the thermal stability of film were analyzed by means of Raman-spectroscope, time-of-flight method, and optical emission spectrum. It was found that the film deposited under higher pressure has less diamond-like character. The film deposited under rest gas or argon atmosphere was very unstable and looked like a little graphite-like character. The film deposited at high vacuum (10-5 mbar rest gas) was the most stable and looked like the most diamond-like character. The film deposited at higher power density was more diamond-like than that at lower power density.

  16. Growth of HT-LiCoO2 thin films on Pt-metalized silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao; CHUNG Chiyuen; ZHU Min

    2008-01-01

    Layered LiCoO2 (HT-LiCoO2) films were grown on Pt-metalized silicon (PMS) substrates and polished bulk nickel (PBN) substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 films. The HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains, whereas on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45 μA·h·cm-2μm-1 with a cycling efficiency of above 99% at the charge/discharge rate of 0.5C.

  17. The perpendicular magnetic anisotropy of CoPt/Au multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, T. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Gao, L. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Zhang, R. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Nicholl, L. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Yan, M.L. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Sellmyer, D.J. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Liou, S.H. [Department of Physics and Astronomy and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)]. E-mail: sliou@unl.edu

    2005-02-01

    We have studied the magnetic properties of Au (2 nm)/Co{sub 50}Pt{sub 50} (3 nm)/Au (2 nm) multilayer films prepared on amorphous Al{sub 2}O{sub 3}/Si and (0 0 1) MgO substrates. The as-deposited films on both substrates are magnetically soft with an FCC structure and exhibit a perpendicular anisotropy. After annealing at 500 deg. C, the sample on the Al{sub 2}O{sub 3}/Si substrate has become magnetically isotropic but the sample on the MgO substrate still has perpendicular anisotropy with FCT structure. This film deposited on the MgO substrate did not show a strong perpendicular anisotropy due to the diffusion of the Au and the (1 1 1) nucleation of initial Au layer. We can obtain a perpendicular anisotropy in the multilayer films without an initial Au layer on a (0 0 1) MgO substrate. After annealing at 400 deg. C, these films have L1{sub 0} phase with (0 0 1) texture and strong perpendicular anisotropy.

  18. The Electrochemical Atomic Layer Deposition of Pt and Pd nanoparticles on Ni foam for the electrooxidation of alcohols

    CSIR Research Space (South Africa)

    Modibedi, RM

    2012-10-01

    Full Text Available Electrodeposition of Pt and Pd metal by surface limited redox replacement reactions was performed using the electrochemical atomic layer deposition. Carbon paper and Ni foam were used as substrates for metal deposition. Supported Pt and Pd...

  19. Photocatalysis and photoinduced hydrophilicity of WO3 thin films with underlying Pt nanoparticles.

    Science.gov (United States)

    Miyauchi, Masahiro

    2008-11-07

    The photocatalytic oxidation and photoinduced hydrophilicity of thin tungsten trioxide (WO(3)) films coupled with platinum (Pt) nanoparticles were investigated. WO(3) films with underlying Pt nanoparticles (WO(3)/Pt/substrate) and those with overlying Pt nanoparticles (Pt/WO(3)/substrate) were synthesized by sputtering and sol-gel methods. Between these films, underlying Pt nanoparticles greatly enhanced the photocatalytic oxidation activity of WO(3) without decreasing the photoinduced hydrophilic conversion. However, overlying Pt nanoparticles deteriorated the hydrophilicity of WO(3) because the Pt nanoparticle surface was hydrophobic. The enhanced photocatalytic reaction by the Pt nanoparticles was attributed to the multi-electron reduction in Pt, which is caused by the injected electrons from the conduction band of WO(3). The relationship between photocatalytic activity and thin film structure, including the size of Pt nanoparticles, the thickness and porosity of the WO(3) layer, were investigated. Consequently, the optimum structure for high performance in both photocatalysis and photoinduced hydrophilicity was WO(3) (50 nm)/Pt(1.5 nm)/substrate, and this film exhibited a significant self-cleaning property even under visible light irradiation.

  20. Preparation of Nano-Particles (Pb,La)TiO3 Thin Films by Liquid Source Misted Chemical Deposition

    Institute of Scientific and Technical Information of China (English)

    张之圣; 曾建平; 李小图

    2004-01-01

    Nano-particles lanthanum-modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h.

  1. Electrical Properties of Sputter-deposited ZrO2-based Pt/ZrO2/Si Capacitors

    Institute of Scientific and Technical Information of China (English)

    Keunbin YIM; Yeonkyu PARK; Anna PARK; Namhee CHO; Chongmu LEE

    2006-01-01

    Pt/ZrO2/Si sandwich structures where ZrO2 is deposited by radio frequency (r.f.) magnetron sputtering using a Zr target in an atmosphere of O2/Ar gas mixture, were fabricated and the effects of the O2/Ar flow ratio in the reactive sputtering process, the annealing temperature, the ZrO2 film thickness on the structure,the surface roughness of ZrO2 films and the electric properties of Pt/ZrO2/Si metal-oxide-semiconductor (MOS) capacitors were investigated. The optimum process parameters of the Pt/ZrO2/Si capacitor based on reactively sputtered-ZrO2 determined in such a way as the capacitance is maximized and the leakage current,the oxide charge, and the interface trap density are minimized that is the O2/Ar flow ratio of 1.5, the annealing temperature of 800℃, and the film thickness of 10 nm. Also the conduction mechanism in the Pt/ZrO2/Si capacitor has been discussed.

  2. Spin Hall magnetoresistance in Co2FeSi/Pt thin films: dependence on Pt thickness and temperature

    Science.gov (United States)

    Huang, Xiufeng; Dai, Zhiwen; Huang, Lin; Lu, Guangduo; Liu, Min; Piao, Hongguang; Kim, Dong-Hyun; Yu, Seong-cho; Pan, Liqing

    2016-11-01

    We have investigated the temperature and the Pt layer thickness dependence of the magnetoresistances (MRs) in Co2FeSi/Pt thin films. Based on the field dependent measurements, it can be seen that the spin-current-induced spin Hall magnetoresistance (SMR) plays the dominant role in the MRs in the Co2FeSi/Pt bilayers in the whole temperature range. Meanwhile, a quite small part of anisotropic magnetoresistance (AMR) existed in the MRs. It proved to be originated from magnetic proximity effect (MPE) by measuring the Pt thickness and temperature dependence of the AMR. Moreover, the Co2FeSi layer thickness has much weaker effect on the SMR and AMR compared to the Pt layer thickness. These results indicate that the Co2FeSi/Pt interface is beneficial to be used in the spin-current-induced physical phenomena.

  3. The role of surface Pt on the coadsorption of hydrogen and CO on Pt monolayer film modified Ru(0001) surfaces

    Science.gov (United States)

    Diemant, T.; Hartmann, H.; Bansmann, J.; Behm, R. J.

    2016-10-01

    We have investigated the impact and role of the Pt surface modification on the coadsorption of hydrogen and CO on structurally well defined bimetallic Pt monolayer island/film modified Ru(0001) surfaces with Pt contents up to a complete Pt layer, employing temperature programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRRAS). Kinetic limitations in the surface diffusion are shown to play an important role for adsorption at 90 K, and lead to profound effects of the dosing sequence on the adsorption and desorption characteristics. Furthermore, they are responsible for spill-over effects during the TPD measurements, where COad becomes mobile and can spill-over from weakly bonding Pt monolayer areas to strongly bonding Pt-free Ru(0001) areas, which displaces Dad from these surface areas. The present findings are discussed in comparison with previous results on related metallic and bimetallic adsorption and coadsorption systems.

  4. Underpotential Deposition of Silver on Pt(111). Part 1. Concentration Dependence

    Science.gov (United States)

    1990-01-01

    AD-A236 692 Underpotential Deposition of Silver on Pt(111): Part I. Concentration Dependence r T ~.J.F. Rodriguez, D.L. Taylor and H.D. Abruhla* EL...dependence of the underpotential deposition of silver on well-defined Pt(111) electrodes. Electrochemical as well as ultra high vacuum surface...silver are deposited at underpotentials but the stability of the second layer is a strong function of the silver ion concentration in solution. When

  5. The Effects of Organic Adsorbates on the Underpotential Deposition of Silver on Pt(111) Electrodes

    Science.gov (United States)

    1993-01-01

    CV) The Effects of Organic Adsorbates on the Underpotential Deposition W.0 of Silver on Pt(111) Electrodes _• D. L. Taylor and H. D. Abruxla* D TIC...to determine the effects of competing organic adsorbates on the underpotential deposition of silver on Pt(111). The adsorbates studied are known to...hcis )n appive tor pubic release and sal Its distribution is unlimited. fu .. 93-12456 INTRODUCTION The process of underpotential deposition (UPD) of

  6. Controlled co-deposition of FePt nanoparticles embedded in MgO: a detailed investigation of structure and electronic and magnetic properties

    Science.gov (United States)

    D'Addato, S.; Grillo, V.; di Bona, A.; Luches, P.; Frabboni, S.; Valeri, S.; Lupo, P.; Casoli, F.; Albertini, F.

    2013-12-01

    Films of FePt nanoparticles (NPs) embedded in MgO were obtained by controlled co-deposition of FePt NPs pre-formed by a gas aggregation source and of Mg evaporated in an oxygen atmosphere. Assemblies of core-shell FePt@MgO NPs and films of FePt NPs embedded in MgO matrix could be obtained by varying FePt and Mg deposition rates. Transmission electron microscopy (TEM) and high resolution-TEM revealed the core-shell structure of the NPs, with an FePt core (of average diameter = 4.75 nm) presenting a multitwinned icosahedral structure, and MgO partially in crystalline form. The functional effect of the MgO shell in shielding the FePt core from external oxidation was shown with XPS. Upon controlled annealing, a transition from A1 to L10 ordering could be obtained, with structural and morphological re-arrangement. The magnetic hysteresis loops obtained from alternating gradient field magnetometry at room temperature show a ‘wasp-waist’ shape, with small values of coercive field (Hc = 300-1400 Oe), decreasing at increasing amounts of co-deposited MgO.

  7. Controlled co-deposition of FePt nanoparticles embedded in MgO: a detailed investigation of structure and electronic and magnetic properties.

    Science.gov (United States)

    D'Addato, S; Grillo, V; di Bona, A; Luches, P; Frabboni, S; Valeri, S; Lupo, P; Casoli, F; Albertini, F

    2013-12-13

    Films of FePt nanoparticles (NPs) embedded in MgO were obtained by controlled co-deposition of FePt NPs pre-formed by a gas aggregation source and of Mg evaporated in an oxygen atmosphere. Assemblies of core-shell FePt@MgO NPs and films of FePt NPs embedded in MgO matrix could be obtained by varying FePt and Mg deposition rates. Transmission electron microscopy (TEM) and high resolution-TEM revealed the core-shell structure of the NPs, with an FePt core (of average diameter (d) = 4.75 nm) presenting a multitwinned icosahedral structure, and MgO partially in crystalline form. The functional effect of the MgO shell in shielding the FePt core from external oxidation was shown with XPS. Upon controlled annealing, a transition from A1 to L10 ordering could be obtained, with structural and morphological re-arrangement. The magnetic hysteresis loops obtained from alternating gradient field magnetometry at room temperature show a 'wasp-waist' shape, with small values of coercive field (Hc = 300-1400 Oe), decreasing at increasing amounts of co-deposited MgO.

  8. Pulsed laser deposition of barium metaplumbate thin films for ferroelectric capacitors

    Science.gov (United States)

    Mardare, A. I.; Mardare, C. C.; Fernandes, J. R. A.; Vilarinho, P. M.; Joanni, E.

    2003-08-01

    Barium metaplumbate thin films were deposited in situ by pulsed laser deposition on Si/SiO2/Ti/Pt substrates with a high deposition rate. The temperatures used ranged between 400 ^circ C and 700 ^circ C. As the deposition temperature was increased, the films assumed a strong (222) preferential orientation. This orientation of the electrodes was reflected on the PZT films, having a very big influence on their ferroelectric behavior. The PZT films made over BPO deposited at high temperature presented high values of remanent polarization (43 μC/cm^2) but indications of high leakage currents could be observed in the hysteresis loops. By using BPO bottom electrodes, a 30% improvement in the fatigue behavior of PZT capacitors when compared with the normal platinum electrodes was observed.

  9. Effect of oxygen on magnetic properties of Co-Pt-Cr-SiO{sub 2} thin films for perpendicular recording media

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, H. [Akita Research Institute of Advance Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan)]. E-mail: yamane@ait.pref.akita.jp; Watanabe, S. [Akita Research Institute of Advance Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Ariake, J. [Akita Research Institute of Advance Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Honda, N. [Akita Research Institute of Advance Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Ouchi, K. [Akita Research Institute of Advance Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Iwasaki, S. [Tohoku Institute of Technology, 35-1 Yagiyama-Kasumi-cho, Taihaku-ku, Sendai, 982-8577 (Japan)

    2005-02-01

    The effect of oxygen on magnetic properties of Co-Pt-Cr-SiO{sub 2} films deposited with various sputtering conditions of Ar gas pressure and deposition speed was investigated. It was suggested that optimum oxygen composition in the film for obtaining large H{sub c} was to have the oxygen/silicon ratio of 2 in Co-Pt-Cr-Si-O films. No X-ray photoelectron spectroscopy spectrum of Co-O or Cr-O was observed in this film, while the Si spectrum shifted to higher energy indicating Si-O bonding. The film exhibited a well-isolated fine grain structure, and the oxygen/silicon ratio was almost constant throughout the depth. It is suggested that the granular structure with SiO{sub 2} grain boundaries is formed from the initial deposition stage.

  10. An investigation of the internal temperature dependence of Pd-Pt cluster beam deposition: A molecular dynamics study

    Science.gov (United States)

    Chen, Cha'o.-Kuang; Chang, Shing-Cheng

    2010-02-01

    We investigated the internal temperature dependence of the Pd 1- aPt a cluster beam deposition in the present study via the molecular dynamics simulations of soft-landing. By analysis of the velocity distribution and diffusion coefficient of the bimetallic cluster, Pd atoms with better mobility improved the diffusibility of Pt atoms. The radial composition distribution showed that a Pt-core/Pd-shell structure of the cluster formed at high internal temperatures through migrations of the Pd atoms from inner to surface shells. In the soft-landing process, the diffusing and epitaxial behaviors of the deposited clusters mainly depended on the internal temperature because the incident energy of the cluster was very small. By depositing clusters at high internal temperatures, we obtained a thin film of good epitaxial growth as the energetic cluster impact. Furthermore, nonepitaxial configurations such as scattered nonepitaxial atoms, misoriented particles, and grain boundaries of (1 1 1) planes were produced in the growth of the cluster-assembled film. As the size of the incident cluster increased, the internal temperature of the cluster needed for better interfacial diffusion and contact epitaxy on the substrate also rose.

  11. Pulsed laser deposition of tantalum pentoxide film

    Science.gov (United States)

    Zhang, J.-Y.; Boyd, I. W.

    We report thin tantalum pentoxide (Ta2O5) films grown on quartz and silicon substrates by the pulsed laser deposition (PLD) technique employing a Nd:YAG laser (wavelength λ=532 nm) in various O2 gas environments. The effect of oxygen pressure, substrate temperature, and annealing under UV irradiation using a 172-nm excimer lamp on the properties of the grown films has been studied. The optical properties determined by UV spectrophotometry were also found to be a sensitive function of oxygen pressure in the chamber. At an O2 pressure of 0.2 mbar and deposition temperatures between 400 and 500 °C, the refractive index of the films was around 2.18 which is very close to the bulk Ta2O5 value of 2.2, and an optical transmittance around 90% in the visible region of the spectrum was obtained. X-ray diffraction measurements showed that the as-deposited films were amorphous at temperatures below 500 °C and possessed an orthorhombic (β-Ta2O5) crystal structure at temperatures above 600 °C. The most significant result of the present study was that oxygen pressure could be used to control the composition and modulate optical band gap of the films. It was also found that UV annealing can significantly improve the optical and electrical properties of the films deposited at low oxygen pressures (<0.1 mbar).

  12. Growth of epitaxial Pt thin films on (0 0 1) SrTiO{sub 3} by rf magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Kahsay, A. [Departament de Física Aplicada i Òptica, Universitat de Barcelona, 08028 Barcelona (Spain); Polo, M.C., E-mail: mcpolo@ub.edu [Departament de Física Aplicada i Òptica, Universitat de Barcelona, 08028 Barcelona (Spain); Ferrater, C.; Ventura, J. [Departament de Física Aplicada i Òptica, Universitat de Barcelona, 08028 Barcelona (Spain); Rebled, J.M. [Departament d’Electrònica, Universitat de Barcelona Institut de Nanociència i Nanotecnologia IN 2UB, 08028 Barcelona (Spain); Varela, M. [Departament de Física Aplicada i Òptica, Universitat de Barcelona, 08028 Barcelona (Spain)

    2014-07-01

    The growth of platinum thin film by rf magnetron sputtering on SrTiO{sub 3}(0 0 1) substrates for oxide based devices was investigated. Platinum films grown at temperatures higher than 750 °C were epitaxial ([1 0 0]Pt(0 0 1)//[1 0 0]STO(0 0 1)), whereas at lower temperatures Pt(1 1 1) films were obtained. The surface morphology of the Pt films showed a strong dependence on the deposition temperature as was revealed by atomic force microscopy (AFM). At elevated temperatures there is a three-dimensional (3D) growth of rectangular atomically flat islands with deep boundaries between them. On the other hand, at low deposition temperatures, a two-dimensional (2D) layered growth was observed. The transition from 2D to 3D growth modes was observed that occurs for temperatures around 450 °C. The obtained epitaxial thin films also formed an atomically sharp interface with the SrTiO{sub 3}(0 0 1) substrate as confirmed by HRTEM.

  13. Heteroepitaxial growth of Pt and Au thin films on MgO single crystals by bias-assisted sputtering.

    Science.gov (United States)

    Tolstova, Yulia; Omelchenko, Stefan T; Shing, Amanda M; Atwater, Harry A

    2016-03-17

    The crystallographic orientation of a metal affects its surface energy and structure, and has profound implications for surface chemical reactions and interface engineering, which are important in areas ranging from optoelectronic device fabrication to catalysis. However, it can be very difficult and expensive to manufacture, orient, and cut single crystal metals along different crystallographic orientations, especially in the case of precious metals. One approach is to grow thin metal films epitaxially on dielectric substrates. In this work, we report on growth of Pt and Au films on MgO single crystal substrates of (100) and (110) surface orientation for use as epitaxial templates for thin film photovoltaic devices. We develop bias-assisted sputtering for deposition of oriented Pt and Au films with sub-nanometer roughness. We show that biasing the substrate decreases the substrate temperature necessary to achieve epitaxial orientation, with temperature reduction from 600 to 350 °C for Au, and from 750 to 550 °C for Pt, without use of transition metal seed layers. In addition, this temperature can be further reduced by reducing the growth rate. Biased deposition with varying substrate bias power and working pressure also enables control of the film morphology and surface roughness.

  14. Tuning the Photoelectrocatalytic Hydrogen Evolution of Pt-Decorated Silicon Photocathodes by the Temperature and Time of Electroless Pt Deposition.

    Science.gov (United States)

    Fabre, Bruno; Li, Gaozeng; Gouttefangeas, Francis; Joanny, Loic; Loget, Gabriel

    2016-11-15

    The electroless deposition of Pt nanoparticles (NPs) on hydrogen-terminated silicon (H-Si) surfaces is studied as a function of the temperature and the immersion time. It is demonstrated that isolated Pt structures can be produced at all investigated temperatures (between 22 and 75 °C) for short deposition times, typically within 1-10 min if the temperature is 45 °C or less than 5 min at 75 °C. For longer times, dendritic metal structures start to grow, ultimately leading to highly rough interconnected Pt networks. Upon increasing the temperature from 22 to 75 °C and for an immersion time of 5 min, the average size of the observed Pt NPs monotonously increases from 120 to 250 nm, and their number density calculated using scanning electron microscopy decreases from (4.5 ± 1.0) × 10(8) to (2.0 ± 0.5) × 10(8) Pt NPs cm(-2). The impact of both the morphology and the distribution of the Pt NPs on the photoelectrocatalytic activity of the resulting metallized photocathodes is then analyzed. Pt deposited at 45 °C for 5 min yields photocathodes with the best electrocatalytic activity for the hydrogen evolution reaction. Under illumination at 33 mW cm(-2), this optimized photoelectrode shows a fill factor of 45%, an efficiency (η) of 9.7%, and a short-circuit current density (|Jsc|) at 0 V versus a reversible hydrogen electrode of 15.5 mA cm(-2).

  15. Deposition and Characterization of Zinc Oxide Films

    Directory of Open Access Journals (Sweden)

    Seniye KARAKAYA

    2014-07-01

    Full Text Available Zinc oxide (ZnO is suitable for optoelectronic applications due to its electrical and optical properties. The present work deals with the preparation and characterization of ZnO films deposited by the ultrasonic spray pyrolysis method. The starting solution was zinc acetate. Effects of substrate temperature on films properties have been investigated. Optical properties of the films have been characterized by investigating transmittance, absorbance and photoluminescence (PL spectra. Optical transmission spectrum shows that ZnO films have high transmission (about 80% in visible region for substrate temperatures at 350oC. Surface morphology of the films has also been analyzed by atomic force microscope (AFM. Four probes conductivity measurements have been used for electrical characterization. The resistivity of ZnO films increases with increasing substrate temperatures

  16. A comparative study on the PMA behavior of 5-nm thick Co{sub 49}Pt{sub 51} films grown at room temperature and at high temperature on glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.-Y. [Graduate Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China); Saravanan, P. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Kuo, C.-Y. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Lin, K.-F. [Graduate Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China)

    2014-06-01

    Co{sub 49}Pt{sub 51} alloy films with strong perpendicular magnetic anisotropy (PMA) have been most often grown on either single crystal or glass substrates with deposition temperature of about 350 °C using Pt/Ru as an underlayer. In contrast, in this study, 5-nm thick Co{sub 49}Pt{sub 51} alloy films with significant PMA were fabricated on glass substrates at room temperature (RT) using a combination of Ta and Pt underlayers. The structural and magnetic properties of the Co{sub 49}Pt{sub 51} films obtained at RT (RT-CoPt) were compared with that of those produced by the conventional high-temperature route (HT-CoPt). The x-ray diffraction studies showed the evolution of highly textured Pt (111) peak accompanied by a CoPt (222) shoulder for the RT-CoPt films, similar to that of the HT-CoPt films. The microstructural studies revealed extremely smooth surface with root mean square roughness (R{sub rms}) of 0.5 nm for the RT-CoPt films, while the HT-CoPt films showed wavy surface with R{sub rms} of 2.4 nm. The out-of-plane and in-plane hysteresis loops demonstrated the existence of strong PMA for both the RT-CoPt and HT-CoPt films. The estimated magnetic parameters for the RT-CoPt films such as squarness ratio, SQR (0.96), perpendicular coercivity, H{sub c⊥} (822 Oe) and magneto-crystalline anisotropy constant, K{sub u} (6.4×10{sup 6} erg/cm{sup 3}) was found to be comparable to that of those obtained with the HT-CoPt films (SQR=0.96, H{sub c⊥}=1810 Oe and K{sub u}=7.1×10{sup 6} erg/cm{sup 3}). - Highlights: • 5-nm thick Co{sub 49}Pt{sub 51} films with strong PMA were grown at RT using Ta/Pt underlayers. • Relatively smooth surface (R{sub rms}=0.5 nm) was achieved for the RT-Co{sub 49}Pt{sub 51} films. • Performance of RT-Co{sub 49}Pt{sub 51} was superseding with the conventionally processed one. • High K{sub u} (6.4×10{sup 6} erg/cm{sup 3}), high SQR (0.96) and moderate H{sub c⊥} (822 Oe) were achieved. • The role of Ta and Pt layers for the

  17. Microstructure and magnetic properties of sputtered Fe-Pt thin films

    CERN Document Server

    Mahalingam, T; Chen, J H; Wang, S F; Inoue, K

    2003-01-01

    The characterization of rf magnetron-sputtered Fe-Pt thin films at various compositions (Pt = 15, 24, 46 and 78 at%) is reported. X-ray diffraction studies on annealed Fe-46%Pt thin films at 600 deg C revealed an ordered L1 sub 0 gamma sub 2 -FePt phase with fct structure whereas annealed Fe-24%Pt and Fe-78%Pt films exhibited ordered gamma sub 1 -Fe sub 3 Pt and gamma sub 3 -FePt sub 3 phases, respectively. The effects of argon quenching and rapid thermal annealing (RTA) on the structural and magnetic properties are investigated. When the films are annealed at 600 deg C for 1 h and then quenched to room temperature in argon gas, ordered gamma sub 2 -FePt with L1 sub 0 phase is obtained. Argon-quenched and rapid thermal annealed films exhibit microtwins in scanning electron microscopy analysis. The appearance of microtwins may be attributed to the planar defects developed in the FePt films due to the release of elastic strain during annealing. The saturation magnetization is found to increase with ferrous cont...

  18. Research on Raman-scattering and Fabrication of Multilayer Thin Film with Different Structures and Components Based on Pt/Ti/Si3N4/SiO2/Si Substrate

    Institute of Scientific and Technical Information of China (English)

    Qiu-lin Tan; Wen-dong Zhang; Chen-yang Xue; Jun Liu; Jun-hong Li; Ji-jun Xiong

    2009-01-01

    Using the same conditions and various starting materials, such as lead acetate trihydrate, tetrabulyl titanate, zirconium n-butoxide, and acetylacetone, two kinds of solid precursors, lead zirconate titanate (PZT, Zr/Ti=15/85) and lead titanate (PT), were fabricated. With three different combinations, namely, PZT, PT/PZT-PZT/PT, and PT/PZT/-/PZT/PT, three multilayer thin films were deposited on three Pt-Ti-Si3N4-SiO2-Si substrates by a modified sol-gel process. The fabrication process of the thin films is discussed in detail. We found that there is a large built-in stress in the thin film, which can be diminished by annealing at 600 ℃, when the gel is turned into solid material through drying and sintering. The Raman scattering spectra of the films with different compositions and structures were investigated. With the help of X-ray diffraction (XRD) analyzer and Raman scattering spectra analyzer, it was found that the thin films with the PT/PZT-PZT/PT structure have reasonable crystallinity and less residual stress. XRD testing shows that the diffraction pattern of the multilayer film results from the superimposition of the PZT and PT patterns. This leads to the conclusion that the PT/PZT-PZT/PT multilayer thin film has a promising future in pyroelectric infrared detectors with high performance.

  19. High-purity cobalt thin films with perpendicular magnetic anisotropy prepared by chemical vapor deposition

    Science.gov (United States)

    Ootera, Yasuaki; Shimada, Takuya; Kado, Masaki; Quinsat, Michael; Morise, Hirofumi; Nakamura, Shiho; Kondo, Tsuyoshi

    2015-11-01

    A study of the chemical vapor deposition (CVD) of high-purity cobalt thin films is described. The Co layer prepared by a thermal CVD technique with a Pt/Ta underlayer and a Pt cap layer shows a saturation magnetization (Ms) of ∼1.8 T and perpendicular magnetic anisotropy (PMA) with an anisotropy energy (Ku) of ∼105 J/m3. The cobalt thickness dependence of Ku reveals that the interfacial anisotropy at the Pt/Co interface is most likely the origin of the obtained PMA.

  20. Platinum thin films with good thermal and chemical stability fabricated by inductively coupled plasma-enhanced atomic layer deposition at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bo-Heng [Instrument Technology Research Center, National Applied Research Laboratories, Taiwan (China); Huang, Hung Ji, E-mail: hjhuang@itrc.narl.org.tw [Instrument Technology Research Center, National Applied Research Laboratories, Taiwan (China); Huang, Sheng-Hsin [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Hsiao, Chien-Nan [Instrument Technology Research Center, National Applied Research Laboratories, Taiwan (China)

    2014-09-01

    The inductively coupled plasma-enhanced atomic layer deposition (PEALD) method was used to fabricate ultrathin and smooth Pt thin films at low temperatures without the use of a Pt seed layer. The Pt thin metal films deposited at 200 °C onto Si and glass substrates exhibited high conductivities (< 12 μΩ cm for films with a thickness greater than 8 nm) and thermal stabilities resembling those of the bulk material. The measured density of the deposited Pt thin films was 20.7 ± 6 g/cm{sup 3}. X-ray photoelectron spectra of the films showed clear 4f peaks (74.3 eV (4f{sub 5/2}) and 71.1 eV (4f{sub 7/2})), and X-ray diffraction measurements showed the (111) peak of the fcc structure. The deposited Pt layers were in crystal form. The 25.5-nm Pt films coated onto 170-nm-wide trench structures (aspect ratio of 3.5:1) exhibited good step coverage. The PEALD-deposited Pt thin films were chemically stable under high-temperature light illumination and could serve as catalysts under strongly alkaline conditions (pH = 12) during the long-term oxidization of ammonium ions. - Highlights: • Inductively coupled plasma applied to enhance atomic layer deposition (PEALD) • Smooth Pt films fabricated by PEALD at low temperature • 8-nm Pt shows clear metal peaks in XPS and XRD. • 8-nm Pt shows low electrical resistivity of 16 μΩ cm. • 8-nm Pt shows stability under strong light and pH = 12 wash by NH{sub 4}{sup +}/NaOH solution.

  1. Iron films deposited on porous alumina substrates

    Science.gov (United States)

    Yamada, Yasuhiro; Tanabe, Kenichi; Nishida, Naoki; Kobayashi, Yoshio

    2016-12-01

    Iron films were deposited on porous alumina substrates using an arc plasma gun. The pore sizes (120 - 250 nm) of the substrates were controlled by changing the temperature during the anodic oxidation of aluminum plates. Iron atoms penetrated into pores with diameters of less than 160 nm, and were stabilized by forming γ-Fe, whereas α-Fe was produced as a flat plane covering the pores. For porous alumina substrates with pore sizes larger than 200 nm, the deposited iron films contained many defects and the resulting α-Fe had smaller hyperfine magnetic fields. In addition, only a very small amount of γ-Fe was obtained. It was demonstrated that the composition and structure of an iron film can be affected by the surface morphology of the porous alumina substrate on which the film is grown.

  2. Magnetoelectric properties of epitaxial Fe3O4 thin films on (011) PMN-PT piezosubstrates

    Science.gov (United States)

    Tkach, Alexander; Baghaie Yazdi, Mehrdad; Foerster, Michael; Büttner, Felix; Vafaee, Mehran; Fries, Maximilian; Kläui, Mathias

    2015-01-01

    We determine the magnetic and magnetotransport properties of 33 nm thick Fe3O4 films epitaxially deposited by rf-magnetron sputtering on unpoled (011) [PbMg1/3Nb2/3O3] 0.68-[PbTiO3]0.32 (PMN-PT) substrates. The magnetoresistance (MR), as well as the magnetization reversal, strongly depend on the in-plane crystallographic direction of the epitaxial (011) Fe3O4 film and strain. When the magnetic field is applied along [100], the magnetization loops are slanted and the sign of the longitudinal MR changes from positive to negative around the Verwey transition at 125 K on cooling. Along the [01 1 ¯] direction, the loops are square shaped and the MR is negative above the switching field across the whole temperature range, just increasing in absolute value when cooling from 300 K to 150 K. The value of the MR is found to be strongly affected by poling the PMN-PT substrate, decreasing in the [100] direction and slightly increasing in the [01 1 ¯] direction upon poling, which results in a strained film.

  3. Fabrication of Pt deposited on carbon nanotubes and performance of its polymer electrolyte membrane fuel cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new method of depositing nano-sized Pt particles on the surface of the carbon nano-tubes was introduced, and the performance of Pt/carbon nanotube compound on polymer electrolyte membrane fuel cells was measured. The experimental results show that the fine platinum particles (about 3 nm) were well dispersed on carbon nanotubes, which demonstrates the excellent catalytic properties of the Pt/CNTs compound in polymer electrolyte membrane fuel cells.

  4. Laser deposition of bimetallic island films

    Science.gov (United States)

    Kucherik, A. O.; Arakelyan, S. M.; Kutrovskaya, S. V.; Osipov, A. V.; Istratov, A. V.; Vartanyan, T. A.; Itina, T. E.

    2016-08-01

    In this work the results of a bimetallic Au-Ag structure deposition from the colloidal system by nanosecond laser radiation are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. We report the results of formation bimetallic islands films with various electrical and optical properties. The changes in the optical properties of the obtained thin films are found to depend on their morphology.

  5. Microstructure and conduction behavior of BiFeO3 thin film deposited on Ge-doped ZnO

    Science.gov (United States)

    Raghavan, Chinnambedu Murugesan; Choi, Ji Ya; Kim, Sang Su

    2017-02-01

    BiFeO3 (BFO) thin films were deposited on a Ge-doped ZnO (GZO)/Si(100) and a Pt(111)/Ti/SiO2/Si(100) using a pulsed laser deposition technique. An improved crystal growth property was observed for the BFO thin film deposited on the GZO/Si(100). The BFO thin film, which was deposited on the (00 l) textured GZO/Si(100), exhibited preferred ( l00) orientated grains, while randomly orientated grains were observed for the thin film deposited on the Pt(111)/Ti/SiO2/Si(100). When compared with the Pt/BFO/Pt capacitor, the GZO/BFO/GZO capacitor exhibited improved conduction behaviors, such as a low leakage current density and high stability against electrical breakdown. From the J-E curves, conduction of the GZO/BFO/GZO and the Pt/BFO/Pt capacitors was found to be dominated by Ohmic and space charge limited conductions at low and high electric field, respectively.

  6. SnO2/Pt Thin Film Laser Ablated Gas Sensor Array

    Directory of Open Access Journals (Sweden)

    Rahman Wagiran

    2011-08-01

    Full Text Available A gas sensor array was developed in a 10 × 10 mm2 space using Screen Printing and Pulse Laser Ablation Deposition (PLAD techniques. Heater, electrode, and an insulator interlayer were printed using the screen printing method on an alumina substrate, while tin oxide and platinum films, as sensing and catalyst layers, were deposited on the electrode at room temperature using the PLAD method, respectively. To ablate SnO2 and Pt targets, depositions were achieved by using a 1,064 nm Nd-YAG laser, with a power of 0.7 J/s, at different deposition times of 2, 5 and 10 min, in an atmosphere containing 0.04 mbar (4 kPa of O2. A range of spectroscopic diffraction and real space imaging techniques, SEM, EDX, XRD, and AFM were used in order to characterize the surface morphology, structure, and composition of the films. Measurement on the array shows sensitivity to some solvent and wood smoke can be achieved with short response and recovery times.

  7. SnO2/Pt thin film laser ablated gas sensor array.

    Science.gov (United States)

    Shahrokh Abadi, Mohammad Hadi; Hamidon, Mohd Nizar; Shaari, Abdul Halim; Abdullah, Norhafizah; Wagiran, Rahman

    2011-01-01

    A gas sensor array was developed in a 10 × 10 mm(2) space using Screen Printing and Pulse Laser Ablation Deposition (PLAD) techniques. Heater, electrode, and an insulator interlayer were printed using the screen printing method on an alumina substrate, while tin oxide and platinum films, as sensing and catalyst layers, were deposited on the electrode at room temperature using the PLAD method, respectively. To ablate SnO(2) and Pt targets, depositions were achieved by using a 1,064 nm Nd-YAG laser, with a power of 0.7 J/s, at different deposition times of 2, 5 and 10 min, in an atmosphere containing 0.04 mbar (4 kPa) of O(2). A range of spectroscopic diffraction and real space imaging techniques, SEM, EDX, XRD, and AFM were used in order to characterize the surface morphology, structure, and composition of the films. Measurement on the array shows sensitivity to some solvent and wood smoke can be achieved with short response and recovery times.

  8. Physical Vapor Deposition of Thin Films

    Science.gov (United States)

    Mahan, John E.

    2000-01-01

    A unified treatment of the theories, data, and technologies underlying physical vapor deposition methods With electronic, optical, and magnetic coating technologies increasingly dominating manufacturing in the high-tech industries, there is a growing need for expertise in physical vapor deposition of thin films. This important new work provides researchers and engineers in this field with the information they need to tackle thin film processes in the real world. Presenting a cohesive, thoroughly developed treatment of both fundamental and applied topics, Physical Vapor Deposition of Thin Films incorporates many critical results from across the literature as it imparts a working knowledge of a variety of present-day techniques. Numerous worked examples, extensive references, and more than 100 illustrations and photographs accompany coverage of: * Thermal evaporation, sputtering, and pulsed laser deposition techniques * Key theories and phenomena, including the kinetic theory of gases, adsorption and condensation, high-vacuum pumping dynamics, and sputtering discharges * Trends in sputter yield data and a new simplified collisional model of sputter yield for pure element targets * Quantitative models for film deposition rate, thickness profiles, and thermalization of the sputtered beam

  9. Dependence of grain sizes and microstrains on annealing temperature in Fe/Pt multilayers and L1{sub 0} FePt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zotov, Nikolay [Institute for Materials, Ruhr-University Bochum, 44780 Bochum (Germany)], E-mail: Nikolay.Zotov@ruhr-uni-bochum.de; Feydt, Juergen [Forschungszentrum Caesar, Ludwig-Erhard-Allee 2, 53175 Bonn (Germany); Ludwig, Alfred [Institute for Materials, Ruhr-University Bochum, 44780 Bochum (Germany)

    2008-11-28

    Fe/Pt multilayers (MLs) with an overall composition Fe{sub 52}Pt{sub 48}, deposited by magnetron sputtering on thermally oxidized Si wafer substrates, were post annealed in vacuum at various temperatures (T{sub A}) in the range 573-973 K. The MLs transform directly and completely into polycrystalline hard-magnetic FePt thin films with ordered L1{sub 0} structure above T{sub A} = 573 K. The evolution of the microstructure, the order parameter and the stacking fault density with annealing temperature was investigated by ex-situ X-ray diffraction and line-broadening analysis. The average microstrains of the thin films are relatively small ( {approx} 0.2%) and remain practically constant as a function of T{sub A}. The thin films show anisotropic size-broadening and grain growth: fast growth rate along the [221] direction and a slow growth rate along the [001] direction. The annealing temperature dependence of the average grain size could be described by a grain growth model with grain growth exponent n = 3 {+-} 0.5 and activation energy 0.51 {+-} 0.07 eV.

  10. Magnetic and structural investigation of magnetic thin films with obliquely deposited underlayers

    CERN Document Server

    Hadley, M J

    2002-01-01

    An in-plane uniaxial magnetic anisotropy has been observed in thin Co films normally deposited onto obliquely sputtered Ta and Pt underlayers. Associated with this anisotropy is an augmented easy axis coercivity. The in-plane easy axis is, in most cases, perpendicular to the incident deposition plane. Microstructural results indicate that grains are well connected along the magnetic easy axis but are separated by long continuous voids along the hard axis, which is ascribed to a geometric shadowing effect due to the oblique incidence deposition of the underlayer. Hence, the magnetic anisotropy mimics the film growth anisotropy. It is therefore believed that the observed magnetic properties are due to magnetostatic shape anisotropy effects. In-plane coercivity and anisotropy field are shown to increase with underlayer deposition angle, underlayer thickness and magnetic layer thickness. The choice of capping layer is also observed to dramatically alter the magnetics, as did the sample temperature. In general, Pt...

  11. Enhancing the perpendicular magnetic anisotropy of Co-Pt(P) films by epitaxial electrodeposition onto Cu(1 1 1) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zana, Iulica [Department of Metallurgical and Materials Engineering, Tuscaloosa, AL 35487-0209 (United States): Center for Materials for Information Technology, Tuscaloosa, AL 35487-0209 (United States)]. E-mail: iz7@mail.gatech.edu; Zangari, Giovanni [Center for Materials for Information Technology, Tuscaloosa, AL 35487-0209 (United States): Department of Materials Science and Engineering and Center for Electrochemical Science and Engineering, University of Virginia, Charlottesville, VA 22904-4745 USA (United States); Shamsuzzoha, Mohamad [Department of Metallurgical and Materials Engineering, Tuscaloosa, AL 35487-0209 (United States): School of Mines and Energy Development, University of Alabama, Tuscaloosa, AL 35487-0209 (United States)

    2005-04-15

    Co-rich, Co-Pt alloy films containing {approx}20 at% Pt and small amounts of P, with thickness from 125 to 1000 nm have been galvanostatically (constant current) grown by electroplating onto Cu seed layers with strong (1 1 1) orientation. The influence of deposition current density (cd=10-50 mA/cm{sup 2}) and film thickness on their growth morphology, structural and magnetic properties have been investigated. When electrodeposited on Cu(1 1 1), Co-Pt(P) films develop a microstructure consisting of a disordered hexagonal-closed-packed (hcp) matrix with {l_brace}0 0 0 1{r_brace} preferential orientation. At low cd, a small amount of simple cubic L1{sub 2} phase was detected, which disappears altogether by increasing cd to 50 mA/cm{sup 2}. The plated films show saturation magnetization in the range 775-832 kA/m (778-832 emu/cm{sup 3}), large perpendicular magnetic anisotropy up to 1.02 MJ/m{sup 3} (1.02x10{sup 7} erg/cm{sup 3}), and coercivity up to 486 kA/m (6.1 kOe) in the out-of-plane direction. The perpendicular anisotropy was found to originate predominantly from the high magnetocrystalline anisotropy of the hcp phase of Co-Pt(P) with c-axis perpendicular to the substrate.

  12. Microstructure and magnetic properties of FePt/MgO multilayers deposited by RF magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    Xiaoli Li; Fang Wang; Fengxian Jiang; Xiaohong Xu; Haishun Wu

    2008-01-01

    FePt (50 rim) and [FePt(a nm)/MgO(b nm)]5/glass (a=1, 2, 3; b=1, 2, 3)films Were prepared by radio frequency (RF) magnetron sputtering technique, and then were annealed at 600℃ for 30 min. The effect of MgO layer thickness on the structures and magnetic properties of the FePt/MgO multilayers was investigated. The coercivities and inter-grain interactions of the FePt/MgO films were decreased, yet the degree of (001) texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FePt/MgO films with appropriate coercivities, high perpendicular anisotropy, and weak inter- grain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FePt/MgO nanos- tructured films are promising candidates for future high-density perpendicular recording media. C 2008 University of Science and Technology Beijing. All fights reserved.

  13. Impact of IrRu oxygen evolution reaction catalysts on Pt nanostructured thin films under start-up/shutdown cycling

    Science.gov (United States)

    Cullen, David A.; More, Karren L.; Atanasoska, Ljiljana L.; Atanasoski, Radoslav T.

    2014-12-01

    Electron microscopy and X-ray photoelectron spectroscopy (XPS) were utilized to study the role of oxygen evolution reaction (OER) catalysts in mitigating degradation arising from start-up/shutdown events. Pt nanostructured thin films (NSTF) were coated with a Ru0.1Ir0.9 OER catalyst at loadings ranging from 1 to 10 μg cm-2 and submitted to 5000 potential cycles within a membrane electrode assembly. Analysis of the as-deposited catalyst showed that the Ir and Ru coating is primarily metallic, and further evidence is provided to support the previously reported interaction between Ru and the perylene-red support. Aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy were used to observe the impact of the OER catalysts on Pt dissolution and migration into the membrane. Elemental mapping showed a high percentage of the Ir catalyst was maintained on the NSTF whisker surfaces following testing. The presence of the OER catalysts greatly reduced the smoothing of the Pt NSTF whiskers, which has been correlated with Pt dissolution and losses in electrochemically active surface area. The dissolution of both Ir and Pt led to the formation of IrPt nanoparticle clusters in the membrane close to the cathode, as well as the formation of a Pt band deeper in the membrane.

  14. The microstructure and magnetic properties of electrodeposited Co-Pt thin films on Ru buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, G.H. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)], E-mail: skk94@skku.edu; Lee, C.H.; Jang, J.H. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, N.J. [Department of Materials Science and Engineering, Kumoh National University of Technology, Kumi 730-701 (Korea, Republic of); Suh, S.J. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Advanced Materials and Process Research Center for IT, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2008-11-15

    For high-density magnetic recording media, this study examined the crystal structure and the texture of electrodeposited cobalt-platinum (Co-Pt) films on Ru buffer layer. A 15-nm-thick Co-Pt film exhibited very high out-of-plane coercivity and squareness, which were 6248 Oe and 0.89, respectively. The coercivity, H{sub c}, of Co-Pt films grown on Ru buffer layer decreased significantly with increasing thickness, possibly due to the lattice misfit of 5.4% between Co-Pt and Ru, leading to the decrease of perpendicular magnetic anisotropy (PMA) of Co-Pt films as indicated by the observed hexagonal-closed-packed (HCP) (1 1-bar 0 1) plane of Co-Pt films. According to nano beam diffraction pattern (NBDP), however, Co-Pt film grown on Ru layer of HCP exhibited mixed HCP and FCC phases. Also, cross-sectional TEM image suggests that the high PMA may result from the columnar structure of physically isolated Co-Pt grains with the c-axis perpendicular to the film plane.

  15. Deposition of highly (111)-oriented PZT thin films by using metal organic chemical deposition

    CERN Document Server

    Bu, K H; Choi, D K; Seong, W K; Kim, J D

    1999-01-01

    Lead zirconate titanate (PZT) thin films have been grown on Pt/Ta/SiNx/Si substrates by using metal organic chemical vapor deposition with Pb(C sub 2 H sub 5) sub 4 , Zr(O-t-C sub 4 H sub 9) sub 4 , and Ti(O-i-C sub 3 H sub 7) sub 4 as source materials and O sub 2 as an oxidizing gas. The Zr fraction in the thin films was controlled by varying the flow rate of the Zr source material. The crystal structure and the electrical properties were investigated as functions of the composition. X-ray diffraction analysis showed that at a certain range of Zr fraction, highly (111)-oriented PZT thin films with no pyrochlore phases were deposited. On the other hand, at low Zr fractions, there were peaks from Pb-oxide phases. At high Zr fractions, peaks from pyrochlore phase were seen. The films also showed good electrical properties, such as a high dielectric constant of more than 1200 and a low coercive voltage of 1.35 V.

  16. Deposition of biopolymer films on micromechanical sensors

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Gammelgaard, Lene; Jensen, Marie P.

    2011-01-01

    The influence of various parameters on the spray-coating of thin films of poly(l-lactide) (PLLA) was investigated. The optimized processing conditions were used for deposition of the biodegradable polymer on arrays of SU-8 microcantilevers. The resonance frequency of the cantilevers before and af...

  17. Selective deposition of Pt onto supported metal clusters for fuel cell electrocatalysts

    Science.gov (United States)

    Jeon, Tae-Yeol; Pinna, Nicola; Yoo, Sung Jong; Ahn, Docheon; Choi, Sun Hee; Willinger, Marc-Georg; Cho, Yong-Hun; Lee, Kug-Seung; Park, Hee-Young; Yu, Seung-Ho; Sung, Yung-Eun

    2012-09-01

    We report a new method for deposition of Pt on a metal core to develop real electrocatalysts with significantly reduced amounts of expensive Pt as well as enhanced activity for oxygen reduction reaction. Ru and Pd have different crystal structures and modify the electronic structure of Pt to a different extent (shifts in d-band center). They were chosen as core materials to examine whether hydroquinone dissolved in ethanol can be used to deposit additional Pt atoms onto preformed core nanoparticles, and whether the modified d-character of Pt on different host metals can result in the enhanced ORR activity. The physicochemical characteristics of Pd-Pt and Ru-Pt core-shell nanoparticles are investigated. The core-shell structure was identified through a combination of experimental methods, employing electron microscopy, electrochemical measurements, and synchrotron X-ray measurements such as powder X-ray diffraction, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. The hydroquinone reduction method proved to be an excellent route for the epitaxial growth of a Pt shell on the metal cores, leading to enhanced ORR activities.We report a new method for deposition of Pt on a metal core to develop real electrocatalysts with significantly reduced amounts of expensive Pt as well as enhanced activity for oxygen reduction reaction. Ru and Pd have different crystal structures and modify the electronic structure of Pt to a different extent (shifts in d-band center). They were chosen as core materials to examine whether hydroquinone dissolved in ethanol can be used to deposit additional Pt atoms onto preformed core nanoparticles, and whether the modified d-character of Pt on different host metals can result in the enhanced ORR activity. The physicochemical characteristics of Pd-Pt and Ru-Pt core-shell nanoparticles are investigated. The core-shell structure was identified through a combination of experimental methods, employing electron microscopy

  18. Pulsed laser deposition of nanostructured Ag films

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Tony [School of Physics, Trinity College, Dublin 2 (Ireland); Doggett, Brendan [School of Physics, Trinity College, Dublin 2 (Ireland); Lunney, James G. [School of Physics, Trinity College, Dublin 2 (Ireland)]. E-mail: jlunney@tcd.ie

    2006-04-30

    Ultra-thin (0.5-5 nm) films of Ag have been prepared by pulsed laser deposition in vacuum using a 26 ns KrF excimer laser at 1 J cm{sup -2}. The deposition was controlled using a Langmuir ion probe and a quartz crystal thickness monitor. Transmission electron microscopy showed that the films are not continuous, but are structured on nanometer size scales. Optical absorption spectra showed the expected surface plasmon resonance feature, which shifted to longer wavelength and increased in strength as the equivalent film thickness was increased. It is shown that Maxwell Garnett effective medium theory can be used to calculate the main features of optical absorption spectra.

  19. Pt-based Thin Films as Efficient and Stable Catalysts for Oxygen Electroreduction

    DEFF Research Database (Denmark)

    Zamburlini, Eleonora

    This thesis presents the fabrication and characterization of Pt-based thin film catalysts for Oxygen Reduction Reaction (ORR). Gadolinium and Yttrium have been used as alloying materials, in preparation for the replacement of the traditional but economically disadvantageous pure Pt catalysts...... at the cathode of Polymer Electrolyte Membrane Fuel Cells (PEMFCs). Herein the fabrication method, which consists of co-sputtering of thin films, is presented in detail, explaining the challenges one must face in order to fabricate oxygen-free Pt-lanthanides and Pt-early transition metals alloys...... be due to the different kind of surfaces generated by sputtering. Both the Pt5Gd and Pt3Y films maintain over 80 % of the initial ORR activity when cycled 10000 times between 0.6 and 1.0 V vs. RHE in 0.1 M HClO4, and that is an indicator of the good stability of these catalysts. Investigation...

  20. Electro-Deposition Pt Catalysts Supported on Carbon-Nanotubes for Methanol Oxidation

    Institute of Scientific and Technical Information of China (English)

    Hailin Song; Peixia Yang; Xiaoyu Wen; Maozhong An; Jinqiu Zhang

    2015-01-01

    In order to study the properties of supporting Pt catalysts for methanol oxidation, carbon⁃nanotubes are used by electrochemical deposition method. Different deposition turns, different cyclic voltammetry scanning speeds and processing time with ascorbic acid are investigated in this paper. The micrographs of Pt/CNTs catalysts are characterized by scanning electron microscopy, the electro⁃catalytic properties of Pt/CNTs catalysts for methanol oxidation are investigated by cycle voltammetry and chronoamperometry. The results show that the size of platinum will be greater with the faster scanning speed. After dissolution in ascorbic acid, Pt nano⁃particles disperse uniformly. The obtained Pt/CNTs catalysts show a high electro⁃catalytic activity and stability.

  1. Columnar structured FePt films epitaxially grown on large lattice mismatched intermediate layer

    Science.gov (United States)

    Dong, K. F.; Deng, J. Y.; Peng, Y. G.; Ju, G.; Chow, G. M.; Chen, J. S.

    2016-09-01

    The microstructure and magnetic properties of the FePt films grown on large mismatched ZrN (15.7%) intermediate layer were investigated. With using ZrN intermediate layer, FePt 10 nm films exhibited (001) texture except for some weaker FePt (110) texture. Good epitaxial relationships of FePt (001) //ZrN (001) //TiN (001) among FePt and ZrN/TiN were revealed from the transmission electron microscopy (TEM) results. As compared with TiN intermediate layer, although FePt-SiO2-C films grown on ZrN/TiN intermediate layer showed isotropic magnetic properties, the large interfacial energy and lattice mismatch between FePt and ZrN would lead to form columnar structural FePt films with smaller grain size and improved isolation. By doping ZrN into the TiN layer, solid solution of ZrTiN was formed and the lattice constant is increased comparing with TiN and decreased comparing with ZrN. Moreover, FePt-SiO2-C films grown on TiN 2 nm-20 vol.% ZrN/TiN 3 nm intermediate layer showed an improved perpendicular magnetic anisotropy. Simultaneously, columnar structure with smaller grain size retained.

  2. Growth and properties of electrodeposited cobalt films on Pt/Si(1 0 0) surface

    Energy Technology Data Exchange (ETDEWEB)

    Azizi, A.; Sahari, A.; Felloussia, M.L.; Schmerber, G.; Meny, C.; Dinia, A

    2004-04-30

    In this paper, the growth, structural and magnetic properties of cobalt (Co) films electrodeposited on a Pt/Si(1 0 0) substrate have been investigated. Co films with metallic appearance were obtained from aqueous solution of 0.1 M CoSO{sub 4}, 10 mM CoCl{sub 2} as the source of metal ions and 1 M Na{sub 2}SO{sub 4} as a supporting electrolyte with 0.5 M H{sub 3}BO{sub 3} at pH 4.2. This electrochemical technique indicated a deposition peak signature of limited diffusion growth with the transition from progressive to instantaneous nucleation mechanism. The atomic force microscopy (AFM) images showed a granular structure of the electrodeposited layers. X-ray measurements (XRD) and nuclear magnetic resonance (NMR) indicate a small grain size with the presence of a mixture of Co hcp and fcc structures. The magnetic properties of the deposited films were investigated with a magnetic field in the parallel and perpendicular direction and showed that the easy magnetization axis is in the plane.

  3. Enhanced coercivity of HCP Co-Pt alloy thin films on a glass substrate at room temperature for patterned media

    Science.gov (United States)

    Chen, Y. S.; Sun, An-Cheng; Lee, H. Y.; Lu, Hsi-Chuan; Wang, Sea-Fue; Sharma, Puneet

    2015-10-01

    High coercivity (Hc) Co-rich type Co-Pt alloy thin films with a columnar grain structure were deposited at room temperature (RT) by magnetron sputtering. Films with a thickness (t) of up to 10 nm had a FCC structure and exhibited soft magnetic properties. When t>25 nm, the magnetic anisotropy changed from in-plane to isotropic. Hc was also enhanced with increasing t and found to be maximum at t=50 nm. The in-plane and out-of-plane Hc of the film was 2.2 and 2.7 kOe, respectively. Further increasing t led to a slight decrease in Hc. Microstructure and phase structure studies revealed columnar Co-Pt grains with a uniform lateral size grown on a 7 nm initial layer. Films with t>25 nm showed a HCP phase, due to the internal stress and volume effect. The microstructural details responsible for the enhanced RT magnetic properties of the HCP Co-Pt alloy thin films were investigated by TEM.

  4. Aerosol deposition of Ba0.8Sr0.2TiO3 thin films

    Directory of Open Access Journals (Sweden)

    Branković Zorica

    2009-01-01

    Full Text Available In this work we optimized conditions for aerosol deposition of homogeneous, nanograined, smooth Ba0.8Sr0.2TiO3 thin films. Investigation involved optimization of deposition parameters, namely deposition time and temperature for different substrates. Solutions were prepared from titanium isopropoxide, strontium acetate and barium acetate. Films were deposited on Si (1 0 0 or Si covered by platinum (Pt (1 1 1 /Ti/SiO2/Si. Investigation showed that the best films were obtained at substrate temperature of 85ºC. After deposition films were slowly heated up to 650ºC, annealed for 30 min, and slowly cooled. Grain size of BST films deposited on Si substrate were in the range 40-70 nm, depending on deposition conditions, while the same films deposited on Pt substrates showed mean grain size in the range 35-50 nm. Films deposited under optimal conditions were very homogeneous, crackfree, and smooth with rms roughness lower than 4 nm for both substrates.

  5. Thermal-vacancy-assisted phase transition in FePt thin films

    Science.gov (United States)

    Li, X. H.; Wang, F. Q.; Liu, B. T.; Guo, D. F.; Zhang, X. Y.

    2011-04-01

    Understanding the ordering transition from A1 to L10 structure in FePt thin films is of great significance for developing L10-FePt films as ultrahigh density magnetic recording media. Here, the L10-ordering transition of FePt films has been investigated based on activation volume measurements. A large activation volume ΔV ∗=10-11 Å3=(0.75-0.8) Ω, where Ω is average atomic volume of FePt, is determined for atomic diffusions in the L10-ordering transition, indicating a thermal-vacancy-assisted phase transition. This transition is suggested to be predominantly dependent on the diffusion of Fe atoms. These findings have direct implications for yielding L10-FePt films at low temperatures and optimizing their microstructures.

  6. Pt crystalline ultrathin films as counter electrodes for bifacial dye-sensitized solar cells

    Science.gov (United States)

    Cheng, Cheng-En; Lin, Zheng-Kun; Lin, Yu-Chang; Lei, Bi-Chen; Chang, Chen-Shiung; Shih-Sen Chien, Forest

    2017-01-01

    This study is to develop the Pt crystalline ultrathin films as high-transparent, efficient, and low-Pt-loaded counter electrodes (CEs) for bifacial dye-sensitized solar cells (DSCs). The 1-nm-thick Pt ultrathin films are sputtered on fluorine-doped tin oxide substrates and thermal annealed at 400 °C. After annealing, as-prepared amorphous-nanocrystal-mixed Pt films become high-crystalline films with better optical transmittance and electrocatalytic ability to I3 - reduction for bifacial DSCs. The rear-to-front ratios of short-circuit current density and power conversion efficiency of DSCs with crystalline ultrathin Pt CEs are as high as 81 and 83%, respectively.

  7. Highly (001) oriented L1{sub 0}-CoPt/TiN multilayer films on glass substrates with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    An, Hongyu; Sannomiya, Takumi; Muraishi, Shinji; Nakamura, Yoshio; Shi, Ji, E-mail: shi.j.aa@m.titech.ac.jp [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Xie, Qian; Zhang, Zhengjun [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, Jian [National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

    2015-03-15

    To obtain strong perpendicular magnetic anisotropy (PMA) based on L1{sub 0} structure for magnetic storage devices, costly single crystalline substrates are generally required to achieve (001) texture. Recently, various studies also have focused on depositing different kinds of seed layers on glass or other amorphous substrates to promote (001) preferred orientation of L1{sub 0} CoPt and FePt. TiN is a very promising seed layer material because of its cubic crystalline structure (similar to MgO) and excellent diffusion barring property even at high temperatures. In the present work, highly (001) oriented L1{sub 0}-CoPt/TiN multilayer films have been successfully deposited on glass substrates. After annealing at 700 °C, the film exhibits PMA, and a strong (001) peak is detected from the x-ray diffraction profiles, indicating the ordering transformation of CoPt layers from fcc (A1) to L1{sub 0} structure. It also is found that alternate deposition of cubic TiN and CoPt effectively improves the crystallinity and (001) preferred orientation of CoPt layers. This effect is verified by the substantial enhancement of (001) reflection and PMA with increasing the period number of the multilayer films.

  8. Dielectric behavior and phase transition of perovskite PMN-PT films

    Energy Technology Data Exchange (ETDEWEB)

    Fan Huiqing; Chen Jin, E-mail: hqfan3@163.co [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an 710072 (China)

    2010-05-01

    The dielectric properties of perovskite relaxor ferroelectrics 0.80Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.20PbTiO{sub 3} (0.80PMN-0.20PT) thick films fabricated by electrophoretic deposition were investigated as a function of temperature and frequency. The phase transformation of 0.80PMN-0.20PT thick films has two different kinds of phase transition: one is a diffused phase transition around the temperature of dielectric permittivity maxima and the other is a first-order transition from frequency dispersion relaxor ferroelectrics to normal ferroelectrics. The frequency and temperature dependence of the dielectric permittivity maximum was also analyzed to discuss the physical meaning of the Debey, Vogel-Fulcher (V-F) and new-glass (N-G) relations. It is shown that the N-G relation is more suitable to characterize the relaxation behavior than the Debey and V-F relations.

  9. Perpendicular Magnetization Behavior of Low- Temperature Ordered FePt Films with Insertion of Ag Nanolayers

    Directory of Open Access Journals (Sweden)

    Da-Hua Wei

    2016-03-01

    Full Text Available FePt-Ag nanocomposite films with large perpendicular magnetic anisotropy have been fabricated by alternate-atomic-layer electron beam evaporation onto MgO(100 substrates at the low temperature of 300 °C. Their magnetization behavior and microstructure have been studied. The surface topography was observed and varied from continuous to nanogranular microstructures with insertion of Ag nanolayers into Fe/Pt bilayer films. The measurement of angular-dependent coercivity showed a tendency of the domain-wall motion as a typical peak behavior shift toward more like a coherent Stoner-Wohlfarth rotation type with the insertion of Ag nanolayers into the FePt films. On the other hand, the inter-grain interaction was determined from a Kelly-Henkel plot. The FePt film without insertion of Ag nanolayers has a positive δM, indicating strong exchange coupling between neighboring grains, whereas the FePt film with insertion of Ag nanolayers has a negative δM, indicating that inter-grain exchange coupling is weaker, thus leading to the presence of dipole interaction in the FePt–Ag nanogranular films. The magnetic characteristic measurements confirmed that the perpendicular magnetization reversal behavior and related surface morphology of low-temperature-ordered FePt(001 nanogranular films can be systematically controlled by the insertion of Ag nanolayers into the FePt system for next generation magnetic storage medium applications.

  10. Potentiostatic Deposition and Characterization of Cuprous Oxide Thin Films

    OpenAIRE

    2013-01-01

    Electrodeposition technique was employed to deposit cuprous oxide Cu2O thin films. In this work, Cu2O thin films have been grown on fluorine doped tin oxide (FTO) transparent conducting glass as a substrate by potentiostatic deposition of cupric acetate. The effect of deposition time on the morphologies, crystalline, and optical quality of Cu2O thin films was investigated.

  11. Crystallographic origin of perpendicular magnetic anisotropy in CoPt film: polarized x-ray absorption study

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, K.K.M.; Chen, J.S.; Liu, T.; Sun, C.J.; Chow, G.M.; (NU Sinapore); (ORNL)

    2009-09-17

    Crystallographic structure, growth induced miscibility gap and strain in Ta/Co{sub 100-x}Pt{sub x} (0 {le} x {le} 43 at%)/Ru/Ta/glass films deposited at ambient temperature were investigated using polarized x-ray absorption spectroscopy to clarify the origin of observed perpendicular magnetic anisotropy (PMA) in Co{sub 72}Pt{sub 28} film. Extended x-ray absorption fine structure spectroscopy data at Co K-edge showed that Co has a similar local atomic environment and averaged interatomic distance in the in-plane and out-of-plane polarization geometries for Co{sub 72}Pt{sub 28}, ruling out the contribution of magneto-elastic anisotropy and growth induced structural anisotropy as the origin of PMA. A large PMA in Co{sub 72}Pt{sub 28} film was attributed to the preferred hexagonal close-packed stacking as observed using the x-ray absorption near-edge structure spectroscopy.

  12. Silicon carbide and other films and method of deposition

    Science.gov (United States)

    Mehregany, Mehran (Inventor); Zorman, Christian A. (Inventor); Fu, Xiao-An (Inventor); Dunning, Jeremy (Inventor)

    2011-01-01

    A method of depositing a ceramic film, particularly a silicon carbide film, on a substrate is disclosed in which the residual stress, residual stress gradient, and resistivity are controlled. Also disclosed are substrates having a deposited film with these controlled properties and devices, particularly MEMS and NEMS devices, having substrates with films having these properties.

  13. New methods of controlled monolayer-to-multilayer deposition of Pt for designing electrocatalysts at an atomic level

    Directory of Open Access Journals (Sweden)

    J. X. WANG

    2001-12-01

    Full Text Available Two new methods for monolayer-to-multileyer Pt deposition are presented. One involves Pt deposition by the replacement of an UPD metal monolayer on an electrode surface and the other the spontaneous deposition of Pt on Ru. The first method, exemplified by the replacement of a Cu monolayer on a Au(111 surface, occurs as a spontaneous irreversible redox reaction in which the Cu monolayer is oxidized by Pt cations, which are reduced and simultaneously deposited. The second method is illustrated by the deposition of Pt on a Ru(0001 surface and on carbon-supported Ru nanoparticles. This deposition takes place upon immersion of a UHV-prepared Ru(0001 crystal or Ru nanoparticles, reduced in H2, in a solution containing PtCl62- ions. The oxidation of Ru to RuOH by a local cell mechanism appears to be coupled with Pt deposition. This method facilitates the design of active Pt-Ru catalysts with ultimately low Pt loadings. Only a quarter of a monolayer of Pt on Ru nanoparticles yields an electrocatalyst with higher activity and CO tolerance for H2/CO oxidation than commercial Pt-Ru alloy electrocatalysts with considerably higher Pt loadings.

  14. Energy barrier versus switching field for patterned Co80Pt20 alloy and Co/Pt multilayer films

    NARCIS (Netherlands)

    de Vries, Jeroen; Bolhuis, Thijs; Abelmann, Leon

    2013-01-01

    Two Co/Pt multilayer samples have been fabricated with a difference in the number of bilayers, leading to a total magnetic layer thickness of 3nm and 20nm. From these films, large arrays of magnetic islands have been patterned using laser interference lithography and ion beam etching. We have

  15. Pulsed laser deposition of ferroelectric thin films

    Science.gov (United States)

    Sengupta, Somnath; McKnight, Steven H.; Sengupta, Louise C.

    1997-05-01

    It has been shown that in bulk ceramic form, the barium to strontium ratio in barium strontium titanium oxide (Ba1- xSrxTiO3, BSTO) affects the voltage tunability and electronic dissipation factor in an inverse fashion; increasing the strontium content reduces the dissipation factor at the expense of lower voltage tunability. However, the oxide composites of BSTO developed at the Army Research Laboratory still maintain low electronic loss factors for all compositions examined. The intent of this study is to determine whether such effects can be observed in the thin film form of the oxide composites. The pulsed laser deposition (PLD) method has been used to deposit the thin films. The different compositions of the compound (with 1 wt% of the oxide additive) chosen were: Ba0.3Sr0.7TiO3, Ba0.4Sr0.6TiO3, Ba0.5Sr0.5TiO3, Ba0.6Sr0.4TiO3, and Ba0.7Sr0.3TiO3. The electronic properties investigated in this study were the dielectric constant and the voltage tunability. The morphology of the thin films were examined using the atomic force microscopy. Fourier transform Raman spectroscopy was also utilized for optical characterization of the thin films. The electronic and optical properties of the thin films and the bulk ceramics were compared. The results of these investigations are discussed.

  16. VUV-light-induced deposited silica films

    Science.gov (United States)

    Buck, Christopher K.; Pedraza, Anthony J.; Benson, Roberto S.; Park, Jae-Won

    1998-05-01

    A novel technique to deposit dielectric films at room temperature is described. The deposition of the silica takes place inside a cylindrical glass chamber where a silent discharge is generated between two electrodes connected to a high voltage, high frequency AC source. The chamber contains two parallel glass tubes where the electrodes are located and is filled with argon or xenon at a pressure of 100 mbar. Under these conditions, it has been shown that high intensity VUV light is generated peaking at 126 nm for argon and at 172 nm for xenon. This VUV radiation seems to produce photoablation of the glass tubes that surround the electrodes. Upon operation of the lamp, polyimide, polypropylene and silicon wafer substrates lying at the bottom of the vessel became coated with silica. The films, identified using X-ray photoelectron spectroscopy (XPS), revealed that the silica is oxygen-deficient with a composition of SiO x where x is between 1.7 and 1.8. The deposition rate on silicon wafers was measured by ellipsometry. When Xe gas is used the deposition rate is much lower than when Ar is used. This result is consistent with a photoablation process since the energy of the photons generated in Ar peaks at 10 eV while those generated in Xe peaks at 7 eV. These energy values should be compared with the O-Si bond strength energy that is 8.3 eV. The morphology and structure of the films were examined by scanning and transmission electron microscopies. Deposition of carbonaceous films occurred when the glass tubes containing the electrodes were coated with carbon.

  17. Study on micro-structure and morphological evolution of Fe/Pt nano-magnetic film.

    Science.gov (United States)

    Ishiguro, S; Ju, D Y; Ogatsu, R; Nakano, T

    2011-10-01

    One of the vertical magnetic recordings medium materials of the hard disk drive (HDD) is a Fe/Pt thin film. The development of ultra-high density magnetic recording medium in next generation is expected the magnetic disks such as HDD with capacity enlargement of the data. In order to study effectiveness of the proposed sputtering method, we evaluated micro structure, magnetic and the mechanical properties of a Fe/Pt thin film by some sputtering process conditions. From research results, effect sputtering conditions on micro-structure and mechanical properties of Fe/Pt nano film are verified.

  18. Composition influence on the microstructures and magnetic properties of FePt thin films

    Institute of Scientific and Technical Information of China (English)

    Liu Li-Wang; Dang Hong-Gang; Sheng Wei; Wang Ying; Cao Jiang-Wei; Bai Jian-Min; Wei Fu-Lin

    2013-01-01

    The FexPt100-x (10 nm) (x =31-51) thin films are fabricated on Si (100) substrates by using magnetron sputtering.The highly ordered L10 FePt phase is obtained after post-annealing at 700 ℃C in Fe47Pt53 thin film.The sample shows good perpendicular anisotropy with a square loop and a linear loop in the out-of-plane and the in-plane direction,respectively.The variations of the magnetic domains are investigated in the films when the content value of Fe changes from 31% to 51%.

  19. Pulsed laser deposition of pepsin thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kecskemeti, G. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary)]. E-mail: kega@physx.u-szeged.hu; Kresz, N. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Smausz, T. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Hopp, B. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Nogradi, A. [Department of Ophthalmology, University of Szeged, H-6720, Szeged, Koranyi fasor 10-11 (Hungary)

    2005-07-15

    Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ({lambda} = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm{sup 2}. The pressure in the PLD chamber was 2.7 x 10{sup -3} Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm{sup 2}. The protein digesting capacity of the transferred pepsin was tested by adapting a modified 'protein cube' method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

  20. Deposition and characterization of CuInS2 thin films deposited over copper thin films

    Science.gov (United States)

    Thomas, Titu; Kumar, K. Rajeev; Kartha, C. Sudha; Vijayakumar, K. P.

    2015-06-01

    Simple, cost effective and versatile spray pyrolysis method is effectively combined with vacuum evaporation for the deposition of CuIns2 thin films for photovoltaic applications. In the present study In2s3 was spray deposited over vacuum evaporated Cu thin films and Cu was allowed to diffuse in to the In2S3 layer to form CuInS2. To analyse the dependence of precursor volume on the formation of CuInS2 films structural, electrical and morphological analzes are carried out. Successful deposition of CuInS2thin films with good crystallinity and morphology with considerably low resistivity is reported in this paper.

  1. Chemically ordered face-centred tetragonal Fe–Pt nanoparticles embedded SiO2 films

    Indian Academy of Sciences (India)

    Sourav Pramanik; Goutam De

    2012-12-01

    Chemically ordered face-centred tetragonal (fct) Fe–Pt alloy nanoparticles (NPs) embedded SiO2 films were synthesized on glass substrate by in situ hybrid sol–gel approach followed by heating at 450–900 °C in air and reducing (10% H2–90% Ar) atmospheres. Heat treatment of Fe/Pt co-doped films in air caused generation of Pt NPs first. At this stage, Fe remained in ionic state covalently bonded with silica network. Further heat treatment at 800–900 °C in reducing atmosphere facilitated the formation of uniformly dispersed fct Fe–Pt alloy NPs in amorphous SiO2 film matrix. The generated alloy composition was estimated by grazing incidence X-ray diffraction and TEM analysis to be Fe0.42Pt0.58 which is close to the nominal value.

  2. Room-temperature magneto-dielectric response in multiferroic ZnFe2O4/PMN-PT bilayer thin films

    Science.gov (United States)

    Garg, T.; Kulkarni, A. R.; Venkataramani, N.

    2016-08-01

    The magneto-dielectric response in multiferroic ZnFe2O4/PMN-PT bilayer thin films prepared on a glass substrate using RF magnetron sputtering has been investigated in this work. PMN-PT thin films (i.e. PMN-PT/LCMO/Pt/Ti/glass) deposited on glass were used as a substrate for deposition of ZnFe2O4 thin films. ZnFe2O4 thin films were annealed ex situ at different temperatures. Structural, magnetic, ferroelectric, dielectric and magneto-dielectric studies were carried out on these multiferroic bilayer thin films. Structural studies revealed the presence of each layer in its respective single phase. Magnetic and ferroelectric studies revealed the ferromagnetic and ferroelectric behaviors of these bilayers. To quantify the magnetoelectric coupling, the dielectric constant of the bilayer was measured at room temperature as a function of frequency with and without the applied magnetic field. The magneto-dielectric response MD(%) was calculated by finding the relative change in dielectric constant at 1 kHz as a percentage. The observed MD response was correlated with magnetization of the ferrite layer. An MD response of 2.60% was found for a bilayer film annealed at 350 °C. At this particular annealing temperature, the ZnFe2O4 layer also has the highest saturation magnetization of 1900 G.

  3. Preparation and characterization of nanostructured Pt/TiO2 thin films treated using electron beam.

    Science.gov (United States)

    Shin, Joong-Hyeok; Woo, Hee-Gweon; Kim, Bo-Hye; Lee, Byung Cheol; Jun, Jin

    2010-05-01

    Pt nanoparticle-doped titanium dioxide (Pt/TiO2) thin films were prepared on a silicon wafer substrate by sol-gel spin coating process. The prepared thin films were treated with electron beam (EB at 1.1 MeV, 100, 200, 300 kGy) at air atmosphere. The effect of EB-irradiation on the composition of the treated thin films, optical properties and morphology of thin films were investigated by various analytical techniques such as X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The crystal structure of the TiO2 layer was found to be an anatase phase and the size of TiO2 particles was determined to be about 13 nm. Pt nanoparticles with diameter of 5 nm were observed on surface of the films. A new layer (presumed to be Pt-Ti complex and/or PtO2 compound) was created in the Pt/TiO2 thin film treated with EB (300 kGy). The transmittance of thin film decreased with EB treatment whereas the refractive index increased.

  4. Underpotential deposition of Cu on Pt(001): Interface structure and the influence of adsorbed bromide

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, C.A. [Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool, L697ZE (United Kingdom); Markovic, N.M.; Ross, P.N. [Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

    1998-05-01

    Using {ital in situ} x-ray diffraction, we studied the underpotential deposition (UPD) of copper onto a Pt(001) electrode both in pure perchloric acid and in the presence of bromide anions. In pure perchloric acid, the Cu is deposited in pseudomorphic p(1{times}1) islands. In the presence of bromide anions, the strong Pt-Br interaction significantly broadens the potential range of Cu UPD. We propose that Br remains in the interface region throughout the UPD process, at first in a disordered Cu-Br phase and then, at more negative potential, forming a c(2{times}2) closed-packed monolayer on top of the completed p(1{times}1) Cu monolayer. The structures are compared to those found during Cu UPD onto Pt(111), and explained in terms of the metal-halide interactions and the Pt surface atomic geometry. {copyright} {ital 1998} {ital The American Physical Society}

  5. Size dependence of thermoelectric power of Au, Pd, Pt nanoclusters deposited onto HOPG surface

    OpenAIRE

    Borisyuk, P. V.; V. I. Troyan; Lebedinskii, Yu Yu; Vasilyev, O S

    2016-01-01

    The paper presents the study of tunnel current-voltage characteristics of Au, Pd and Pt nanoclusters deposited onto the highly oriented pyrolytic graphite (HOPG) surface by pulsed laser deposition. The analysis of tunnel current-voltage characteristics obtained by scanning tunneling spectroscopy (STS) allowed to recover the thermoelectric power value of nanoclusters. It was found that the value of thermoelectric power of pulsed laser deposited nanoclusters depends on nanocluster material and ...

  6. Colloidal processing of PMN-PT thick films for piezoelectric sensor applications

    Science.gov (United States)

    Luo, Hongyu

    65%Pb(Mg1/3Nb2/3)O3-35%PbTiO3 (65PMN-35PT, or PMN-PT) is a highly piezoelectric ceramic with superior piezoelectric coefficients over the more popular Pb(Zr0.5Ti0.5)O 3 (PZT). Because of its complex chemistry and high volatility of lead above 1000°C, the perovskite phase of PMN-PT is hard to process and has prevented PMN-PT from various piezoelectric applications, especially in the new area of piezoelectric micro-electro-mechanical systems (PMEMS) involving thick or thin piezoelectric films. In this thesis, a novel precursor suspension method is introduced that substantially lowers the sintering temperature of PMN-PT to 850°C from a PMN precursor powder made by coating Mg(OH) 2 on Nb2O5 particles. The precursor suspension method entails suspending PMN powders in PT precursor and uses the reaction sintering capability of PMN with nano-sized PT in the temperature range of 800°C˜1000°C. Moreover, free-standing PMN-PT thick films were obtained by tape casting the PMN-PT powder. This new geometry of PMN-PT shows giant electric-field enhanced piezoelectric responses comparable with those of single crystals. As an example of application, the PMN-PT thick film is bonded to a thinner layer of copper by electroplating and made into piezoelectric cantilever sensors. In conclusion, the colloidal suspension processing method produces free-standing PMN-PT thick films with ultrahigh piezoelectric properties.

  7. Effects of Ru and Ag cap layers on microstructure and magnetic properties of FePt ultrathin films.

    Science.gov (United States)

    Liu, Mingfeng; Jin, Tianli; Hao, Liang; Cao, Jiangwei; Wang, Ying; Wu, Dongping; Bai, Jianmin; Wei, Fulin

    2015-01-01

    The effects of Ru and Ag cap layers on the microstructure and magnetic properties of the FePt ultrathin films have been investigated. The results indicate that i) The Ag cap layer segregates from the FePt/Ag bilayer, lowers the FePt ordering temperature, promotes the FePt thin films to form island structure, and enhances the coercivity; ii) The Ru cap layer increases the FePt ordering temperature, helps to maintain smooth continuous structure film, and restrains the FePt (001) orientation and perpendicular magnetic anisotropy (PMA). The effects become more pronounced for the 3-nm-thick FePt thin films. The effects can be mainly attributed to the different melting point and thermal expansion stress between the cap layer and FePt thin films.

  8. Effects of Ru and Ag cap layers on microstructure and magnetic properties of FePt ultrathin films

    Science.gov (United States)

    Liu, Mingfeng; Jin, Tianli; Hao, Liang; Cao, Jiangwei; Wang, Ying; Wu, Dongping; Bai, Jianmin; Wei, Fulin

    2015-04-01

    The effects of Ru and Ag cap layers on the microstructure and magnetic properties of the FePt ultrathin films have been investigated. The results indicate that i) The Ag cap layer segregates from the FePt/Ag bilayer, lowers the FePt ordering temperature, promotes the FePt thin films to form island structure, and enhances the coercivity; ii) The Ru cap layer increases the FePt ordering temperature, helps to maintain smooth continuous structure film, and restrains the FePt (001) orientation and perpendicular magnetic anisotropy (PMA). The effects become more pronounced for the 3-nm-thick FePt thin films. The effects can be mainly attributed to the different melting point and thermal expansion stress between the cap layer and FePt thin films.

  9. Perpendicular magnetic anisotropy of CoPt-AlN composite film with nano-fiber structure

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.C.; Toyoshima, H.; Hashimoto, M. [University of Electro-Communications, Department of Applied Physics and Chemistry, Tokyo (Japan); Shi, J.; Nakamura, Y. [Tokyo Institute of Technology, Department of Metallurgy and Ceramics Science, Tokyo (Japan)

    2005-06-01

    Co-Pt-AlN films were prepared by sputtering a Co-Pt-Al composite target in Ar+N{sub 2} atmosphere. Upon thermal annealing at elevated temperatures, fcc CoPt and a-AlN are formed in the films as phases separated from one other. Both phases develop as fiber-like columnar grains vertical to the substrate and with their lateral size less than 10 nm. Because of the shape anisotropy of the magnetic fiber grains the CoPt-AlN film shows a perpendicular magnetic anisotropy at a thickness equal to or larger than about 25 nm while the Co-TiN and CoPt-TiO{sub 2} films do not unless their thicknesses reach 50 and 100 nm, respectively. This suggests that both the shape anisotropy of the CoPt magnetic fiber grains and their mutual separation in an a-AlN medium work more effectively in the formation with the perpendicular magnetic anisotropy. Such a perpendicular magnetic anisotropy of the CoPt-AlN film associated with the nano-scale feature makes it a very promising candidate for future recording media with ultra-high area density. (orig.)

  10. Tuning morphology and magnetism in epitaxial L10 -FePt films

    Science.gov (United States)

    Lupo, P.; Orna, J.; Casoli, F.; Nasi, L.; Ranzieri, P.; Calestani, D.; Algarabel, P.; Morellón, L.; Albertini, F.

    2013-01-01

    In this work, well-ordered epitaxial FePt thin films have been grown by RF sputtering on two different substrates (MgO (100) and SrTiO3 (100)) and the effect of different lattice parameters between the substrate and FePt film on morphology and magnetic behavior has been considered. Growth conditions have been optimized to obtain different morphologies and magnetic behaviors.

  11. Microstructural evolution and magnetization reversal mechanism of CoPt films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, K K M; Chen, J S; Chow, G M [Department of Materials Science and Engineering, National University of Singapore, Singapore 119260 (Singapore); Hu, J F [Data Storage Institute, Singapore 117608 (Singapore)], E-mail: msecgm@nus.edu.sg

    2009-01-07

    Microstructural evolution and magnetization reversal mechanisms of perpendicular magnetic anisotropic Co{sub 72}Pt{sub 28} films were investigated. Results showed that in the initial stage of film growth, the Co{sub 72}Pt{sub 28} film was continuous and followed a dome-shaped structure with increasing film thickness. When the film thickness further increased above a certain critical value, the film growth acquired an inverted frustum shape structure and increased the intergranular magnetic interaction. The magnetization reversal mechanism showed a strong dependence on microstructures. The magnetization reversal followed the domain wall motion behaviour when the film was continuous and deviated towards the Stoner-Wohlfarth (S-W) model in the dome-shaped regime. A further deviation away from the S-W model was observed, when the film acquired an inverted frustum shape structure in order to minimize the surface energy.

  12. Direct Imaging Mass Spectrometry of Plant Leaves Using Surface-assisted Laser Desorption/Ionization with Sputter-deposited Platinum Film.

    Science.gov (United States)

    Ozawa, Tomoyuki; Osaka, Issey; Hamada, Satoshi; Murakami, Tatsuya; Miyazato, Akio; Kawasaki, Hideya; Arakawa, Ryuichi

    2016-01-01

    Plant leaves administered with systemic insecticides as agricultural chemicals were analyzed using imaging mass spectrometry (IMS). Matrix-assisted laser desorption/ionization (MALDI) is inadequate for the detection of insecticides on leaves because of the charge-up effect that occurs on the non-conductive surface of the leaves. In this study, surface-assisted laser desorption/ionization with a sputter-deposited platinum film (Pt-SALDI) was used for direct analysis of chemicals in plant leaves. Sputter-deposited platinum (Pt) films were prepared on leaves administered with the insecticides. A sputter-deposited Pt film with porous structure was used as the matrix for Pt-SALDI. Acephate and acetamiprid contained in the insecticides on the leaves could be detected using Pt-SALDI-MS, but these chemical components could not be adequately detected using MALDI-MS because of the charge-up effect. Enhancement of ion yields for the insecticides was achieved using Pt-SALDI, accompanied by prevention of the charge-up effect by the conductive Pt film. The movement of systemic insecticides in plants could be observed clearly using Pt-SALDI-IMS. The distribution and movement of components of systemic insecticides on leaves could be analyzed directly using Pt-SALDI-IMS. Additionally, changes in the properties of the chemicals with time, as an indicator of the permeability of the insecticides, could be evaluated.

  13. The effect of Ag layer on the structural and magnetic properties of (001)-oriented [C/CoPt/Ag]{sub 5} films

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xiaohong [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China)]. E-mail: xuxh@dns.sxnu.edu.cn; Jin Tao [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); Li Xiaoli [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); Wang Fang [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); Jiang Fengxian [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); Wu Haishun [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China)

    2007-02-26

    Ordered [C/CoPt/Ag]{sub 5} thin films with (001) preferred orientation have been deposited onto glass substrates by magnetron sputtering. The effects of the Ag layer on the structural and magnetic properties of the [C/CoPt/Ag]{sub 5} films were investigated. We have found that the presence of C sublayer together with the suitable thickness of Ag sublayer can provide a driving force for the chemical ordering of the L1{sub 0} CoPt phase, as well as give an opportunity for the (001)-oriented growth of CoPt grains. It was found that the structural and magnetic properties of CoPt films are strongly related to the strain arising from the misfit between Ag and CoPt layers as well as the C atom diffusion. These three element composite films with a high (001)-oriented growth, a strong perpendicular magnetic anisotropy, and a weak intergrain interactions can satisfy the requirements for ultra-high-density perpendicular recording medium.

  14. Direct observations of ferromagnetic and antiferromagnetic domains in Pt/Co/Cr2O3/Pt perpendicular exchange biased film

    Directory of Open Access Journals (Sweden)

    Yu Shiratsuchi

    2015-11-01

    Full Text Available By using focused soft X-rays, magnetic domain imaging based on X-ray magnetic circular dichroism (XMCD measurements was performed on a Pt/Co/Cr2O3/Pt film that exhibits both perpendicular magnetic anisotropy and perpendicular exchange anisotropy. In the AC-demagnetized state, spatial distributions of the XMCD corresponding to the magnetic domains were clearly observed. In particular, ferromagnetic and antiferromagnetic magnetic domains were separately observed by tuning the photon energy to either the ferromagnetic Co L3 edge or the antiferromagnetic Cr L3 edge. The ferromagnetic domain pattern is similar to the ones previously reported for Co/Pt multilayers, and the ferromagnetic and antiferromagnetic domains are spatially coupled. The magnetization curve measured after cooling the sample, while maintaining the demagnetized state, exhibited positive and negative exchange biases simultaneously, which suggests that the exchange bias is determined on a domain-by-domain basis.

  15. Broadband THz pulse emission and transmission properties of nanostructured Pt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Mingzhe [Department of Physics and Electronics, Liupanshui Normal University, Liupanshui, Guizhou 553004 (China); College of Electronics and Information, Guizhou University, Huaxi 550025, Guiyang, Guizhou (China); Mu, Kaijun; Zhang, Cunlin [Department of Physics, Capital Normal University, Yuquan Road 100082, Beijing (China); Gu, Haoshuang, E-mail: guhs@hubu.edu.cn [Department of Electronic Sci& Tech, Hubei University, Xueyuan Road 430062, Wuhan, Hubei (China); Ding, Zhao [College of Electronics and Information, Guizhou University, Huaxi 550025, Guiyang, Guizhou (China)

    2015-10-01

    The THz transmission and emitting properties of a composite metallic nanostructure, composed of Ag nanowires electrodeposited in an anodic aluminum oxide (AAO) template and a Pt thin film, were investigated by using a femtosecond pulse laser irradiation. The microstructure of the above sub-wavelength nanostructure was investigated by XRD, SEM, AFM and TEM. The results indicated that the thickness of the Pt thin film was about 200 nm and the Ag nanowire array had a sparse and random distribution inside the AAO template, with a length distribution in the range of 10–25 μm. The THz radiation properties of above sub-wavelength nanostructure indicated that the generated THz fluence from the Pt film was a magnitude of μW scale with a broadband frequency range and its subsequent transmission could be significantly improved by the better impedance matching property of the Ag nanowire embedded AAO film compared with that of the empty AAO film.

  16. Fabrication and Surface Properties of Composite Films of SAM/Pt/ZnO/SiO 2

    KAUST Repository

    Yao, Ke Xin

    2008-12-16

    Through synthetic architecture and functionalization with self-assembled monolayers (SAMs), complex nanocomposite films of SAM/Pt/ZnO/SiO2 have been facilely prepared in this work. The nanostructured films are highly uniform and porous, showing a wide range of tunable wettabilities from superhydrophilicity to superhydrophobicity (water contact angles: 0° to 170°). Our approach offers synthetic flexibility in controlling film architecture, surface topography, coating texture, crystallite size, and chemical composition of modifiers (e.g., SAMs derived from alkanethiols). For example, wettability properties of the nanocomposite films can be finely tuned with both inorganic phase (i.e., ZnO/SiO2 and Pt/ZnO/SiO2) and organic phase (i.e., SAMs on Pt/ZnO/SiO2). Due to the presence of catalytic components Pt/ZnO within the nanocomposites, surface reactions of the organic modifiers can further take place at room temperature and elevated temperatures, which provides a means for SAM formation and elimination. Because the Pt/ZnO forms an excellent pair of metal-semiconductors for photocatalysis, the anchored SAMs can also be modified or depleted by UV irradiation (i.e., the films possess self-cleaning ability). Potential applications of these nanocomposite films have been addressed. Our durability tests also confirm that the films are thermally stable and structurally robust in modification- regeneration cycles. © 2008 American Chemical Society.

  17. Field emission from carbon films deposited by VHF CVD on difference substrates

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, A A; Andronov, A N; Felter, T E; Ioffe, A F; Kosarev, A I; Shotov, M V; Vinogradov, A J

    1999-04-01

    As previously demonstrated, non-diamond carbon (NDC) films deposited at low temperatures 200-300 C on silicon tips reduced the threshold of field emission. In this paper we will present the results of the study of field emission from flat NDC films prepared by VHF CVD. Emission measurements were performed in a diode configuration at approximately 10{sup {minus}10} Torr. NDC films were deposited on ceramic and on c-Si substrates sputter coated with layers of Ti, Cu, Ni and Pt. The back contact material influences the emission characteristics but not as a direct correlation to work function. A model of field emission from metal-NDC film structures will be discussed.

  18. Magneto-Optical Detection of the Spin Hall Effect in Pt and W Thin Films

    Science.gov (United States)

    Stamm, C.; Murer, C.; Berritta, M.; Feng, J.; Gabureac, M.; Oppeneer, P. M.; Gambardella, P.

    2017-08-01

    The conversion of charge currents into spin currents in nonmagnetic conductors is a hallmark manifestation of spin-orbit coupling that has important implications for spintronic devices. Here we report the measurement of the interfacial spin accumulation induced by the spin Hall effect in Pt and W thin films using magneto-optical Kerr microscopy. We show that the Kerr rotation has opposite sign in Pt and W and scales linearly with current density. By comparing the experimental results with ab initio calculations of the spin Hall and magneto-optical Kerr effects, we quantitatively determine the current-induced spin accumulation at the Pt interface as 5 ×10-12 μB A-1 cm2 per atom. From thickness-dependent measurements, we determine the spin diffusion length in a single Pt film to be 11 ±3 nm , which is significantly larger compared to that of Pt adjacent to a magnetic layer.

  19. Fabrication of solid-state thin-film batteries using LiMnPO{sub 4} thin films deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Daichi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kuwata, Naoaki, E-mail: kuwata@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Matsuda, Yasutaka; Kawamura, Junichi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Kang, Feiyu [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-03-31

    Solid-state thin-film batteries using LiMnPO{sub 4} thin films as positive electrodes were fabricated and the electrochemical properties were characterized. The LiMnPO{sub 4} thin films were deposited on Pt coated glass substrates by pulsed laser deposition. In-plane X-ray diffraction revealed that the LiMnPO{sub 4} thin films were well crystallized and may have a texture with a (020) orientation. The deposition conditions were optimized; the substrate temperature was 600 °C and the argon pressure was 100 Pa. The electrochemical measurements indicate that the LiMnPO{sub 4} films show charge and discharge peaks at 4.3 V and 4.1 V, respectively. The electrical conductivity of the LiMnPO{sub 4} film was measured by impedance spectroscopy to be 2 × 10{sup −11} S cm{sup −1} at room temperature. The solid-state thin-film batteries that show excellent cycle stability were fabricated using the LiMnPO{sub 4} thin film. Moreover, the chemical diffusion of the LiMnPO{sub 4} thin film was studied by cyclic voltammetry. The chemical diffusion coefficient of the LiMnPO{sub 4} thin film is estimated to be 3.0 × 10{sup −17} cm{sup 2} s{sup −1}, which is approximately four orders magnitude smaller than the LiFePO{sub 4} thin films, and the capacity of the thin-film battery was gradually increased for 500 cycles. - Highlights: • Olivine-type LiMnPO{sub 4} thin-films were fabricated by pulsed laser deposition. • The electrochemical properties were characterized by using solid-state thin-film batteries. • Chemical diffusion coefficient of LiMnPO{sub 4} thin film was estimated by cyclic voltammetry. • Thin-film batteries, Li/Li{sub 3}PO{sub 4}/LiMnPO{sub 4}, show excellent cycle stability up to 500 cycles.

  20. Strontium-Doped Lanthanum Manganite Films Prepared by Magnetic Deposition

    DEFF Research Database (Denmark)

    Menon, Mohan; Larsen, Casper; Andersen, Kjeld Bøhm

    2009-01-01

    Deposition of La0.85Sr0.15MnO3 (LSM) films from suspensions using a magnetic field was found to be a cheap and quick technique. Ninety weight percent of the particles present in the suspensions were deposited within the first minute of the deposition, and the thickness of the film varied linearly...

  1. Resonant infrared pulsed laser deposition of thin biodegradable polymer films

    DEFF Research Database (Denmark)

    Bubb, D.M.; Toftmann, B.; Haglund Jr., R.F.

    2002-01-01

    Thin films of the biodegradable polymer poly(DL-lactide-co-glycolide) (PLGA) were deposited using resonant infrared pulsed laser deposition (RIR-PLD). The output of a free-electron laser was focused onto a solid target of the polymer, and the films were deposited using 2.90 (resonant with O-H str...

  2. Stress in and texture of PVD deposited metal nitride films

    NARCIS (Netherlands)

    Machunze, R.

    2010-01-01

    Thin metal nitride films deposited by Physical Vapor Deposition (PVD) are used amongst many other applications as wear protective coatings in tool industry or as diffusion barriers in integrated circuit technology. Typically these films exhibit a residual in-plane stress when deposited onto rigid su

  3. Synthesis of Pt-Sn core-shell nanoparticles deposited on SBA-15 modified

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Contreras, L.; Alonso-Lemus, I. [Centro de Investigacion en Materiales Avanzados S.C., Laboratorio Nacional de Nanotecnologia (Mexico); Botte, G. G. [Ohio University, Center for Electrochemical Engineering Research, Department of Chemical and Biomolecular Engineering (United States); Verde-Gomez, Y., E-mail: ysmaelverde@yahoo.com [Instituto Tecnologico de Cancun (Mexico)

    2013-07-15

    A novel one-step synthesis method to prepare Pt-Sn bimetallic nanoparticles supported on mesoporous silica with high surface area (SBA-15, 700 m{sup 2}/g) and narrow pore size distribution (around 9.5 nm) was developed. Tin incorporation plays an important dual role, to create active sites into the silica walls that serve as particles anchors center, and to grow Pt-Sn core-shell nanoparticles. High-resolution transmission and scanning electron microscopy, and X-ray diffraction pattern confirm the formation of the Pt-Sn core-shell type nanoparticles ( Almost-Equal-To 1-10 nm). The metal loading was 2.2 and 2.3 wt% for Pt and Sn, respectively. Electron microscopy results show that the metal nanoparticles were deposited not only on the matrix, but also inside of it. Structural, textural, and morphological features of the SBA-15 were slightly affected after the nanoparticles deposition, maintaining its high surface area. The results obtained suggest that Pt-Sn on SBA-15 could be attractive material for several catalytic applications, due to the narrow particle size distribution achieved (from 1 to 10 nm) the high dispersion on the support, as well as the Pt-Sn alloy developed.Graphical Abstract.

  4. Study on hydrogen evolution performance of the carbon supported PtRu alloy film electrodes

    Institute of Scientific and Technical Information of China (English)

    YANG; Bin; LI; Yang; ZAN; Lin-han

    2005-01-01

    The carbon supported PtRu alloy film electrodes having Pt about 0.10 mg/cm2 or even less were prepared by ion beam sputtering method (IBSM). It was valued on the hydrogen analyse performance, the temperature influence factor and the stability by electroanalysis hydrogen analyse method. It was found that the carbon supported PtRu alloy film electrodes had higher hydrogen evolution performance and stability, such as the hydrogen evolution exchange current density (j0) was increase as the temperature (T) rised, and it overrun 150 mA/cm2 as the trough voltage in about 0.68V, and it only had about 2.8% decline in 500 h electrolytic process. The results demonstrated that the carbon supported PtRu alloy film electrodes kept highly catalytic activity and stability, and it were successfully used in pilot plant for producing H2 on electrolysis of H2S.

  5. Electrochemical promotion of propane oxidation on Pt deposited on a dense β″-Al2O3 ceramic Ag+ conductor

    Science.gov (United States)

    Tsampas, Mihalis N.; Kambolis, Anastasios; Obeid, Emil; Lizarraga, Leonardo; Sapountzi, Foteini M.; Vernoux, Philippe

    2013-01-01

    A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β″-Al2O3 ceramic Ag+ conductor was developed and evaluated during propane oxidation. It was observed that, upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation. PMID:24790942

  6. Electrochemical promotion of propane oxidation on Pt deposited on a dense β″-Al2O3 ceramic Ag(+) conductor.

    Science.gov (United States)

    Tsampas, Mihalis N; Kambolis, Anastasios; Obeid, Emil; Lizarraga, Leonardo; Sapountzi, Foteini M; Vernoux, Philippe

    2013-01-01

    A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β″-Al2O3 ceramic Ag(+) conductor was developed and evaluated during propane oxidation. It was observed that, upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation.

  7. CdTe Films Deposited by Closed-space Sublimation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    CdTe films are prepared by closed-space sublimation technology. Dependence of film crystalline on substrate materials and substrate temperature is investigated. It is found that films exhibit higher crystallinity at substrate temperature higher than 400℃. And the CdTe films deposited on CdS films with higher crystallinity have bigger crystallite and higher uniformity. Treatment with CdCl2 methanol solution promotes the crystallite growth of CdTe films during annealing.

  8. Structure and magnetization reversal mechanism in L1{sub 0} FePt films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.J. [Surface Physics State Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China); Zheng Jianguo [Laboratory for Electron and X-ray Instrumentation, Calit2, University of California-Irvine, Irvine, CA 92697 (United States); Shi, Z., E-mail: shizhong@tongji.edu.cn [Surface Physics State Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China); Department of Physics, Tongji University, Shanghai 200092 (China); Zhou, S.M. [Surface Physics State Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China); Department of Physics, Tongji University, Shanghai 200092 (China); Sun, L. [Department of Mechanical Engineering and Texas Center for Superconductivity (TcSUH), University of Houston, Houston, Texas 77204 (United States); Du, J. [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)

    2012-06-30

    A series of L1{sub 0} Fe{sub 63}Pt{sub 37} films with controlled thickness (t{sub FM}) were deposited on MgO(100) substrates for microstructure and magnetization reversal mechanism study. X-ray diffraction measurements show that face-centered tetragonal (200) peak also exists in addition to face-centered tetragonal (002) one, and becomes weak for thick films. High resolution electron microscopy study reveals the existence of periodic misfit dislocations at the FePt/MgO interface and other types of defects such as twins and antiphase boundary inside the film. Out-of-plane initial magnetization shows a slow increase responding to the external magnetic field and then follows a steep increase. The out-of-plane coercivity H{sub C} at room temperature decreases with increasing t{sub FM} and increases when the angle {theta}{sub H} between the external magnetic field and the film normal direction increases. H{sub C} at {theta}{sub H} = 0 changes as a linear function of temperature for individual samples and the slope decreases with increasing t{sub FM}. In addition, magnetic viscosity measurements show that the fluctuation field at room temperature decreases with increasing t{sub FM}. These phenomena indicate that the magnetization reversal in the L1{sub 0} FePt films should be realized by the motion of weakly pinned domain wall and thus governed by the thermal activation model. The magnetization reversal thermal activation volume and corresponding energy increase with increasing t{sub FM}, as a result of the interactions between domain walls and structural defects can be attributed to the sample microstructural characteristic evolution with t{sub FM}. - Highlights: Black-Right-Pointing-Pointer A series of L1{sub 0} Fe{sub 63}Pt{sub 37} films with controlled thickness (t{sub FM}) were prepared. Black-Right-Pointing-Pointer Periodic misfit dislocations are observed at the FePt/MgO interface. Black-Right-Pointing-Pointer The dependence of H{sub C} on t{sub FM} and T is

  9. Switching fields of high-resolution magnetic force microscope tips coated with Co, Co75Pt10Cr15, Co75Pt25, and Co50Pt50 films

    Directory of Open Access Journals (Sweden)

    Ishihara Shinji

    2014-07-01

    Full Text Available Magnetic force microscope (MFM tips are prepared by coating Si tips of 4 nm radius with Co, Co75Pt10Cr15, Co75Pt25, and Co50Pt50 (at. % films of 20 nm thickness at 300 °C. The effects of coating film material on the spatial resolution and the switching field are investigated. Higher resolutions are observed in the order of Co75Pt10Cr15 < (Co50Pt50, Co75Pt25 < Co. The Co-coated tip shows the highest resolution of 7.3 nm, which seems to be depending on a high detection sensitivity related with the magnetic moment of Co material. The saturation magnetization increases in the order of Co75Pt10Cr15 < Co50Pt50 < Co75Pt25 < Co. Higher switching fields are observed in the order of Co < Co75Pt10Cr15 < Co75Pt25 < Co50Pt50. The Co50Pt50-coated tip shows the highest switching field of 1.675±0.025 kOe, which is due to a high coercive field of the magnetic film involving L11 ordered phase with high magnetocrystalline anisotropy energy. The coercive field is recognized in the order of Co < Co75Pt10Cr15 < Co75Pt25 < Co50Pt50. A tip prepared by coating Co50Pt50 film which has high resolution and high switching field is useful for MFM observations of high-density recording media and permanent magnets.

  10. Microstructure and magnetic properties of (001) textured L1(0) FePt films on amorphous glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Speliotis, T; Varvaro, G; Testa, AM; Giannopoulos, G; Agostinelli, E; Li, W; Hadjipanayis, G; Niarchos, D

    2015-05-15

    L1(0) FePt thin films with an island-like morphology and magnetic perpendicular anisotropy were grown at low temperature (300 < T-dep< 375 degrees C) by magnetron sputtering on Hoya glass substrates using a 30-nm thick Cr (2 0 0) underlayer. An MgO buffer layer with a thickness of 2 nm was used to inhibit the diffusion from the Cr underlayer and promote the growth of (0 0 1) oriented L1(0) FePt films by inducing an in-plane lattice distortion. By varying the substrate temperature and the Ar sputter pressure (3.5 < P-Ar< 15 mTorr) during the deposition, the degree of chemical order, the microstructure and the magnetic properties were tuned and the best properties in term of squareness ratio (M-r/M-s similar to 0.95) and coercive field (H-c similar to 14 kOe) were observed for films deposited at T-dep = 350 degrees C and P-Ar= 5 mTorr, due to the appearance of a tensile strain, which favors the perpendicular anisotropy. The analysis of the angular dependence of remanent magnetization curves on the optimized sample suggests that the magnetization reversal is highly incoherent due to the inter-island interactions. Our results provide useful information on the low temperature growth of FePt films with perpendicular anisotropy onto glass substrates, which are relevant for a variety of technological applications, such as magnetic recording and spintronic devices. (C) 2015 Elsevier B.V. All rights reserved.

  11. Purity and resistivity improvements for electron-beam-induced deposition of Pt

    Energy Technology Data Exchange (ETDEWEB)

    Mulders, J.J.L. [FEI Company, Eindhoven (Netherlands)

    2014-12-15

    Electron-beam-induced deposition (EBID) of platinum is used by many researchers. Its main application is the formation of a protective layer and the ''welding material'' for making a TEM lamella with a focused ion beam thinning process. For this application, the actual composition of the deposition is less relevant, and in practice, both the mechanical strength and the conductivity are sufficient. Another important application is the creation of an electrical connection to nanoscale structures such as nano-wires and graphene. To serve as an electrical contact, the resistivity of the Pt deposited structure has to be sufficiently low. Using the commonly used precursor MeCpPtMe{sub 3} for deposition, the resistivity as created by the basic process is 10{sup +5}-10{sup +6} higher than the value for bulk Pt, which is 10.6 μΩ cm. The reason for this is the high abundance of carbon in the deposition. To improve the deposition process, much attention has been given by the research community to parameter optimization, to ex situ or in situ removal of carbon by anneal steps, to prevention of carbon deposition by use of a carbon-free precursor, to electron beam irradiation under a high flux of oxygen and to the combination with other techniques such as atomic layer deposition (ALD). In the latter technique, the EBID structures are used as a 1-nm-thick seed layer only, while the ALD is used to selectively add pure Pt. These techniques have resulted in a low resistivity, today approaching the 10-150 μΩ cm, while the size and shape of the structure are preserved. Therefore, now, the technique is ready for application in the field of contacting nano-wires. (orig.)

  12. Synthesis of Pt nanowires with the participation of physical vapour deposition

    Science.gov (United States)

    Dobrzański, Leszek A.; Szindler, Marek; Pawlyta, Mirosława; Szindler, Magdalena M.; Boryło, Paulina; Tomiczek, Błazej

    2016-01-01

    The following paper presents the possibility of formation of Pt nanowires, achieved by a three-step method consisting of conformal deposition of a carbon nanotube and conformal coverage with platinum by physical vapour deposition, followed by removal of the carbonaceous template. The characterization of this new nanostructure was carried out through scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD).

  13. Synthesis of Pt nanowires with the participation of physical vapour deposition

    Directory of Open Access Journals (Sweden)

    Dobrzański Leszek A.

    2016-01-01

    Full Text Available The following paper presents the possibility of formation of Pt nanowires, achieved by a three-step method consisting of conformal deposition of a carbon nanotube and conformal coverage with platinum by physical vapour deposition, followed by removal of the carbonaceous template. The characterization of this new nanostructure was carried out through scanning electron microscopy (SEM, transmission electron microscopy (TEM and X-ray diffraction (XRD.

  14. Structural and Magnetic Properties of Ultrathin Fe Films on Pt(001) Surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Juan; HE Ke; JIA Jin-Feng; XUE Qi-Kun

    2005-01-01

    @@ Magnetic anisotropy evolution of ultrathin Fe films grown on Pt(001) single-crystal surface is investigated by UHVin situ surface magneto-optical Kerr effect (SMOKE) measurement. After annealing at ~ 600 K, the magnetic anisotropy of Fe film switches from in-plane to perpendicular at low coverage, leading to a spin reorientationtransition (SRT). Meanwhile, in the range of 3-4 monolayer (ML) thickness, the coercivity of the Fe polar hysteresis loop decreases dramatically. Further scanning tunnelling microscopy (STM) and low energy electron diffraction (LEED) investigation correlates the magnetic properties with the film structures. We attribute this SRT to the formation of Fe-Pt ordered alloy.

  15. Microstructure and magnetic properties of FePt film with combined MoC/(Mg-X)O (X=Cu, Ni, Co) intermediate layers

    Science.gov (United States)

    Tsai, Jai-Lin; Tzeng, Jie-Lin; Hu, Keng-Chun; Li, Hsu-Kang; Pan, Zu-Yu; Chang, Yuan-Shuo; Liao, Chang-Chun

    2017-01-01

    The magnetic properties and microstructure of FePt films grown on MoC layer and MoC/(Mg-X)O (X=Cu, Ni, Co) combined intermediate layers were studied. The (Mg-X)O (X=Cu, Ni, Co) layer with thickness of 5 nm was deposited on CrRu seed layer at 395 °C. The CrRu (200) texture was enhanced which may due to well grains growth in specific orientation and small lattice mismatch with (Mg-X)O (X=Cu, Ni, Co). Finally, the FePt/MoC layers were deposited on (Mg-X)O layer at 425 °C. Using MoC/MgCuO combined intermediate layers, the rocking width of FePt (001) and CrRu (200) diffraction peak were changed from 7.1° to 6.1°, and 5.7° to 3.8°, respectively. For MoC/MgCoO dual intermediate layers, the rocking width of FePt (001) and CrRu (200) diffraction peak were 6.7° and 4.1°. The FePt/MoC/MgCoO film illustrates perpendicular magnetic anisotropy with out-of plane coercivity of 9.3 kOe which is higher than FePt film deposited on MoC layer (8.5 kOe) and the in-plane loops is linear. From microstructure, the FePt grains were more separated on MoC/(Mg-X)O (X=Cu, Ni, Co) combined intermediate layers.

  16. Optic fiber hydrogen sensor based on high-low reflectivity Bragg gratings and WO3-Pd-Pt multilayer films

    Science.gov (United States)

    Dai, Jixiang; Yang, Minghong; Li, Zhi; Wang, Gaopeng; Huang, Chujia; Qi, Chongjie; Dai, Yutang; Wen, Xiaoyan; Cheng, Cheng; Guo, Huiyong

    2015-09-01

    A novel optic fiber hydrogen sensor is proposed in this paper. Two Bragg gratings with different reflectivity were written in single mode fiber with phase mask method by 248 nm excimer laser. The end-face of singe mode fiber was deposited with WO3-Pd-Pt multilayer films as sensing element. The peak intensity of low reflectivity FBG is employed for hydrogen characterization, while that of high reflectivity FBG is used as reference. The experimental results show the hydrogen sensor still has good repeatability when the optic intensity in the fiber is only 1/3 of its initial value. The hydrogen sensor has great potential in measurement of hydrogen concentration.

  17. Influence of energetic ions and neutral atoms on the L1 0 ordering of FePt films

    Science.gov (United States)

    Cantelli, V.; von Borany, J.; Mücklich, A.; Zhou, Shengqiang; Grenzer, J.

    2007-04-01

    The A1 → L10 phase transition of Fe50Pt50 films, deposited at room-temperature on amorphous SiO2 by dc magnetron co-sputtering at 0.3 Pa, was studied with in-situ X-ray diffraction. An almost complete transition characterized by a long-range order parameter S > 0.8 is obtained already after a heat treatment at (320 ± 20) °C. A post-deposition He ion irradiation (50 keV, 1 × 1015 - 3 × 1016 cm-2) does not further reduce the transition temperature. Theoretical calculations reveal that, due to the negligible thermalization of the sputtered atoms and reflected ions in the plasma, a considerable fraction of energetic ions and atoms meet the substrate surface. The low transition temperature is explained by the impact of energetic ions and atoms which provoke significant adatom mobility and a decrease of the activation energy for atomic reordering by vacancies. Consequently, using deposition parameters leading to a strong thermalized plasma, the FePt films showed an increase of the transition temperature up to 400 °C, a lower S-value (S ≅ 0.6) and a reduced coercivity.

  18. Formation of Co nanodisc with enhanced perpendicular magnetic anisotropy driven by Ga+ ion irradiation on Pt/Co/Pt films

    Science.gov (United States)

    Sakamaki, M.; Amemiya, K.; Sveklo, I.; Mazalski, P.; Liedke, M. O.; Fassbender, J.; Kurant, Z.; Wawro, A.; Maziewski, A.

    2016-11-01

    The origin of magnetic phase transition from in-plane to perpendicular magnetic anisotropy (PMA) of Pt/Co/Pt thin film by Ga+ ion irradiation at fluences of 1 -5 ×1015 ions /cm2 is investigated by means of x-ray magnetic circular dichroism (XMCD) and extended x-ray absorption fine structure (EXAFS) analyses. We find that Pt and Co atoms are mixed with each other and that Co is oxidized near the surface due to removal of the Pt overlayer. Furthermore, polarization-dependent EXAFS analysis shows that Co is firstly dispersed as separated single-atom-thick sheets in a Pt matrix at 1 ×1015 ions /cm2, then the Co sheets are divided into a few Å clusters at 5 ×1015 ions /cm2, which are regarded as nanodiscs parallel to the film plane. This process is accompanied by the appearance of an out-of-plane magnetization component and a remanence peak is observed. Because we do not observe an enhancement in anisotropy of Co orbital moment which leads to change in magnetic anisotropy through the transition at about 5 ×1015 ions /cm2, it might be possible that such nanodisc formation induces increase of magnetic anisotropy via a shape effect. By comparing with the phase transition observed at lower fluence [Phys. Rev. B 86, 024418 (2012), 10.1103/PhysRevB.86.024418], we find that the mechanism of two transitions is different, i.e., the transition at lower fluence is caused by anisotropy of orbital moment due to structural strain, while the present transition is possibly by shape effect due to nanodisc formation.

  19. Perpendicular magnetic anisotropy and magneto-optical Kerr effect of vapor-deposited Co/Pt-layered structures

    Science.gov (United States)

    Zeper, W. B.; Greidanus, F. J. A. M.; Carcia, P. F.; Fincher, C. R.

    1989-06-01

    We prepared by vapor deposition at room temperature thin (500 Å) Co/Pt multilayers or layered structures directly onto glass or Si substrates. They show a preferential magnetization perpendicular to the film plane for Co thicknesses below 12 Å and a 100% perpendicular remanence for Co thicknesses below 4.5 Å. The magnetic anisotropy can be explained by an interface contribution to the anisotropy. We also investigated the magneto-optical (MO) polar Kerr effect of these multilayers. Because of their excellent magnetic properties and their potentially high oxidation and corrosion resistance, these Co/Pt-layered structures are very promising candidates for MO recording. The Kerr rotation θk at λ=820 nm for a 35×(4.0 Å Co+12.7 Å Pt)-layered structure, which has 100% magnetic remanence, is modest (-0.12°), but the reflectivity R is high (70%), which results in a respectable figure of merit Rθ2k. Furthermore, the Kerr effect increases towards shorter wavelengths and thus favors future higher-density recording.

  20. Preparation of BiFeO3 thin films by pulsed laser deposition method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guan-jun; CHENG Jin-rong; CHEN Rui; YU Sheng-wen; MENG Zhong-yan

    2006-01-01

    BiFeO3 (BFO) thin films were prepared on Pt(111)/TiO2/SiO2/Si(100) substrates by the pulsed-laser deposition (PLD) technique at a low temperature of 450℃. The XRD results indicate that the BFO thin films are of perovskite structure with the presence of small amount of second phases. The oxygen pressures have great effect on the crystalline structures and dielectric properties of BFO thin films. The dielectric constant of the BFO thin films decreases with increasing oxygen pressures,achieving 186,171 and 160 at the frequency of 104 Hz for the oxygen pressures of 0.666,1.333 and 13.332 Pa,respectively. The BFO thin films prepared at the oxygen pressure of 0.666 Pa reveal a saturated hysteresis loop with the remanent polarization of 7.5 μC/cm2 and the coercive field of 176 kV/cm.

  1. Pulsed laser deposition and characterization of Alnico5 magnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Butt, M.Z., E-mail: mzbutt49@yahoo.com [Department of Physics, GC University, Lahore 54000 (Pakistan); Ali, Dilawar [Department of Physics, GC University, Lahore 54000 (Pakistan); Ahmad, Fayyaz [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan); Magnetophotonics Research Laboratory, Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2013-09-01

    Alnico5 films were deposited by pulsed laser deposition on glass substrate at room temperature under a vacuum ∼10{sup −3} Torr in the absence and in the presence of 500 Oe external transverse magnetic field applied on the plasma plume during film deposition. For this purpose, Nd:YAG laser was employed to ablate the Alnico5 target. The ablated material was deposited on glass substrate placed at a distance of 2 cm from the target. The structural and magnetic properties of the film were analyzed by X-ray diffraction, atomic force microscope, and vibrating sample magnetometer. X-ray diffraction patterns showed that the Alnico5 films were amorphous in nature. Atomic force microscopy revealed that the Alnico5 film deposited in absence of external magnetic field has larger root-mean-square roughness value (60.2 nm) than the magnetically deposited film (42.9 nm). Vibrating sample magnetometer measurements showed that the in-plane saturation magnetization of Alnico5 film deposited in the presence of external magnetic field increases by 32% as compared to that for the film deposited in the absence of external magnetic field. However, the out-of-plane saturation magnetization was almost independent of the external magnetic field. In magnetically deposited film, there is in-plane anisotropy parallel to the applied external magnetic field.

  2. Crystalline thin films: The electrochemical atomic layer deposition (ECALD) view

    CSIR Research Space (South Africa)

    Modibedi, M

    2011-09-01

    Full Text Available Electrochemical atomic layer deposition technique is selected as one of the methods to prepare thin films for various applications, including electrocatalytic materials and compound....

  3. Preparation of L11-CoPt/MgO/L11-CoPt tri-layer film on Ru(0001 underlayer

    Directory of Open Access Journals (Sweden)

    Mitsuru Ohtake

    2016-05-01

    Full Text Available A CoPt/MgO/CoPt tri-layer film is prepared on an Ru(0001 single-crystal underlayer at 300 °C by ultra-high vacuum magnetron sputtering. The growth behavior and the crystallographic properties are investigated by reflection high-energy electron diffraction, x-ray diffraction, and cross-sectional transmission electron microscopy. A fully epitaxial CoPt/MgO/CoPt film is formed on the Ru underlayer. The lower CoPt, the MgO, and the upper CoPt layers consist of two (111 variants whose atomic stacking sequences of close-packed plane along the perpendicular direction are ABCABC... and ACBACB... The lower and the upper CoPt layers involve metastable L11 structure, whereas the crystal structure of MgO layer is B1. Flat and atomically sharp interfaces are formed between the layers. The tri-layer film shows a strong perpendicular magnetic anisotropy reflecting the magnetocrystalline anisotropy of L11 crystal. The present study shows that an epitaxial L11-CoPt/MgO/L11-CoPt tri-layer film with perpendicular magnetic anisotropy can be formed by using a low substrate temperature of 300 °C.

  4. Magnetoelectric effect in FeCo/PMN-PT/FeCo trilayers prepared by electroless deposition of FeCo on PMN-PT crystals with various orientations

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H.Q.; Wang, Y.G., E-mail: yingang.wang@nuaa.edu.cn; Xie, D.; Cheng, J.H.

    2014-10-15

    Highlights: • The composites FeCo/PMN-PT/FeCo were prepared by electroless deposition. • The influence of the crystal cut of PMN-PT on ME coupling is discussed. • Optimizing the crystal cut of the piezoelectric substrate, proper resonant frequency and ME effect could be obtained. - Abstract: The magnetoelectric (ME) effect was studied in the FeCo/PMN-PT/FeCo trilayer composites prepared by electroless deposition of the FeCo layers on the single crystal PMN-PT substrates with various crystal cuts. X-ray diffraction reveals that the orientation of PMN-PT substrate has no effect on the growth of FeCo layer. The structures with PMN-PT crystals of various orientations have different acoustic resonance frequencies. FeCo/PMN-PT/FeCo composites with PMN-PT of 〈0 0 1〉{sup L} × 〈01{sup ‾}1〉{sup W} × 〈0 1 1〉{sup T} crystal cut shows superior ME performance, which is due to the highest piezoelectric module of PMN-PT.

  5. Magnetic domain structure in thin CoPt perpendicular magnetic anisotropy films

    Directory of Open Access Journals (Sweden)

    Komine T.

    2013-01-01

    Full Text Available The relation between thickness and domain structure of Co80Pt20 perpendicular magnetic anisotropy films was investigated through experiments and micromagnetic simulation. The films with thickness over 10 nm exhibited clear maze domain structure, while for the films thinner than 10 nm the domain structure abruptly changed from maze domain to irregular and large domain as the thickness became thinner. The irregular domain had narrower domain wall width than maze domain.

  6. The surface morphologies of (Pb, Sr) TiO3 thin film fabricated on Si-buffered Pt/Ti/SiO2/Si substrate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    (Pb, Sr)TiO3 (PST) thin film are fabricated by RF magnetron sputtering on Si-buffered Pt/Ti/SiO2/Si substrates with different buffer layer deposition time. Surface morphologies of the buffer layer indicate an improving surface roughness and larger grains with the prolongation of sputtering time. Deposition of PST thin films shows excellent surface fluctuation filling ability to improve the surface roughness of substrates. PST surface morphologies exhibit apparently different grain forms according to the preparation time durance of buffer layer.

  7. The mechanical properties of thin alumina film deposited by metal-organic chemical vapour deposition

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Gellings, P.J.; Vendel, van de D.; Metselaar, H.S.C.; Corbach, van H.D.; Fransen, T.

    1995-01-01

    Amorphous alumina films were deposited by metal-organic chemical vapour deposition (MOCVD) on stainless steel, type AISI 304. The MOCVD experiments were performed in nitrogen at low and atmospheric pressures. The effects of deposition temperature, growth rate and film thickness on the mechanical pro

  8. Deposition of Aluminium Oxide Films by Pulsed Reactive Sputtering

    Institute of Scientific and Technical Information of China (English)

    Xinhui MAO; Bingchu CAI; Maosong WU; Guoping CHEN

    2003-01-01

    Pulsed reactive sputtering is a novel process used to deposit some compound films, which are not deposited by traditional D.C. reactive sputtering easily. In this paper some experimental results about the deposition of Al oxide films by pulsed reactive sputtering are presented. The hysteresis phenomenon of the sputtering voltage and deposition rate with the change of oxygen flow during sputtering process are discussed.

  9. Room-Temperature Deposition of NbN Superconducting Films

    Science.gov (United States)

    Thakoor, S.; Lamb, J. L.; Thakoor, A. P.; Khanna, S. K.

    1986-01-01

    Films with high superconducting transition temperatures deposited by reactive magnetron sputtering. Since deposition process does not involve significantly high substrate temperatures, employed to deposit counter electrode in superconductor/insulator/superconductor junction without causing any thermal or mechanical degradation of underlying delicate tunneling barrier. Substrates for room-temperature deposition of NbN polymeric or coated with photoresist, making films accessible to conventional lithographic patterning techniques. Further refinements in deposition technique yield films with smaller transition widths, Tc of which might approach predicted value of 18 K.

  10. Preparation of yttria-stabilized zirconia films for solid oxide fuel cells by electrophoretic deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Tatsumi; Sato, Keiji; Mizuhara, Yukako; Takita, Yusaku (Oita Univ. (Japan). Faculty of Engineering)

    1992-06-01

    The electrophoretic deposition (EPD) method was applied for the preparation of yttria-stabilized zirconia (YSZ) films for a solid oxide fuel cell (SOFC). Dense YSZ films with uniform thickness can be readily prepared by EPD method. When the planar SOFC was fabricated by using La[sub 0.6]Sr[sub 0.4]MnO[sub 3] as a cathode and electroless plating Pt as an anode, the open circuit voltage and the maximum power density attained were 1.03 V and 1.87 W cm[sup -2], respectively. (author).

  11. Crystal structure and electrochemical behaviors of Pt/mischmetal film electrodes

    Institute of Scientific and Technical Information of China (English)

    张文魁; 杨晓光; 马淳安; 王云刚; 余厉阳

    2003-01-01

    The Ml(La-rich mischmetal) films with a thin Pt layer on the substrate of chemically coarsen ITO glassor silicon slices were prepared by magnetic sputtering technique. The crystal structure and surface morphology ofthe films were investigated by X-ray diffraction(XRD) analysis and atomic force microscopy(AFM), respectively.The electrochemical hydridation/dehydridation behaviors of the films in KOH solution were studied by using cyclicvoltammagraph and electrochemical impedance spectrum(EIS) as well. The AFM results show that the Pt cover lay-er on the M1 films is of island structure with a grain of 150 - 200 nm in size. The presence of a thin Pt layer can pro-vide sufficient high electrocatalytic activity for the electrochemical charge-transfer reaction. The electrochemical re-duction and oxidation reaction occur on the Pt layer, and the diffusion of H into the Ml film is the rate-controlledstep. The Pt coatings also act as protective layers, preventing oxidation and/or poisoning of the underlying Ml filmsin air.

  12. Deposition of electrochromic tungsten oxide thin films by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Henley, W.B.; Sacks, G.J. [Univ. of South Florida, Tampa, FL (United States). Center of Microelectronics

    1997-03-01

    Use of plasma-enhanced chemical vapor deposition (PECVD) for electrochromic WO{sub 3} film deposition is investigated. Oxygen, hydrogen, and tungsten hexafluoride were used as source gases. Reactant gas flow was investigated to determine the effect on film characteristics. High quality optical films were obtained at deposition rates on the order of 100 {angstrom}/s. Higher deposition rates were attainable but film quality and optical coherence degraded. Atomic emission spectroscopy (AES), was used to provide an in situ assessment of the plasma deposition chemistry. Through AES, it is shown that the hydrogen gas flow is essential to the deposition of the WO{sub 3} film. Oxygen gas flow and tungsten hexafluoride gas flow must be approximately equal for high quality films.

  13. FePtCu alloy thin films: Morphology, L1{sub 0} chemical ordering, and perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, C.; Schletter, H.; Daniel, M.; Matthes, P.; Joehrmann, N.; Makarov, D.; Hietschold, M.; Albrecht, M. [Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); Maret, M. [Laboratory of Science and Engineering of Materials and Processes (SIMaP), INP-Grenoble/CNRS/UJF, F-38402 Saint-Martin d' Heres (France)

    2012-10-01

    Rapid thermal annealing was applied to transform sputter-deposited Fe{sub 51}Pt{sub 49}/Cu bilayers into L1{sub 0} chemically ordered ternary (Fe{sub 51}Pt{sub 49}){sub 100-x}Cu{sub x} alloys with (001) texture on amorphous SiO{sub 2}/Si substrates. It was found that for thin film samples, which were processed at 600 Degree-Sign C for 30 s, the addition of Cu strongly favors the L1{sub 0} ordering and (001) texture formation. Furthermore, it could be revealed by transmission electron microscopy and electron backscatter diffraction that the observed reduction of the ordering temperature with Cu content is accompanied by an increased amount of nucleation sites forming L1{sub 0} ordered grains. The change of the structural properties with Cu content and annealing temperature is closely related to the magnetic properties. While an annealing temperature of 800 Degree-Sign C induces strong perpendicular magnetic anisotropy (PMA) in binary Fe{sub 51}Pt{sub 49} films, the addition of Cu systematically reduces the PMA. However, due to the enhancement of both the A1-L1{sub 0} phase transformation and the development of the (001) texture with increasing Cu content, lowering of the annealing temperature leads to a shift of the maximum perpendicular magnetic anisotropy towards alloys with higher Cu content. Thus, for an annealing temperature of 600 Degree-Sign C, the highest perpendicular magnetic anisotropy energy is found for the (Fe{sub 51}Pt{sub 49}){sub 91}Cu{sub 9} alloy. The smooth surface morphology, adjustable PMA, and high degree of intergranular exchange coupling make these films suitable for post-processing required for specific applications such as for sensorics or magnetic data storage.

  14. On the uniformity of films fabricated by glancing angle deposition

    Science.gov (United States)

    Wakefield, Nicholas G.; Sit, Jeremy C.

    2011-04-01

    Films fabricated using the glancing angle deposition technique are subject to significant variations in several important film parameters across a sample due to geometric conditions that are not uniform across the substrate. This paper presents a method to quantify the non-uniformities in these quantities, starting from a generalized geometric framework, for low-pressure, physical vapor deposition of thin films on substrates of arbitrary size and position. This method is applicable to any glancing angle deposition setup including substrate tilt and rotation but focuses on the case of constant deposition angle and arbitrary azimuthal rotation. While some quantities, such as the effective deposition angle and the deposited mass per unit area at any given point on the substrate can be determined purely from the geometry of the deposition setup, obtaining further quantities, such as the film density and thickness, requires additional, material-specific information that is easily measured.

  15. Structural and magnetic study of thin films based on anisotropic ternary alloys FeNiPt{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Montsouka, R.V.P. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France); Arabski, J. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France); Derory, A. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France); Faerber, J. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France); Schmerber, G. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France); Pierron-Bohnes, V. [IPCMS-GEMME, CNRS UMR 7504, 23 rue du Loess, 67037 Strasbourg Cedex (France)]. E-mail: vero@ipcms.u-strasbg.fr

    2006-01-25

    L1 ordered (Fe-Ni){sub 5}Pt{sub 5} alloy films with perpendicular magnetic anisotropy were successfully prepared by interdiffusing FePt(0 0 1) and NiPt(0 0 1) layers co-deposited on MgO(0 0 1) substrates by MBE. The [0 0 1] growth direction corresponds to the epitaxy of the alloy on the substrate and is the interesting growth orientation to get a perpendicular magnetization. The X-ray diffraction shows a high L1 chemical order (S = 0.7 {+-} 0.1). The easy magnetization direction is perpendicular for all samples. The MFM images display highly interconnected stripes corresponding to up and down orientations of the magnetization. Large uniaxial magnetic anisotropy (K {sub u} 9.10{sup 5} J/m{sup 3}) and suitable magnetic transition temperature (T {sub C} = 400 K) are obtained. The addition of Ni changes the spin-orbit interaction in the FePt compound system, hence causes a decrease of anisotropy, saturation magnetization and coercivity.

  16. In situ X-ray diffraction based investigation of crystallization in solution deposited PZT thin films

    Science.gov (United States)

    Nittala, Krishna

    further investigate the effect of adhesion layer on the crystallization behavior of these films, PZT films were solution deposited onto substrates with titanium (Ti), titanium oxide (TiO x) and zinc oxide (ZnO) adhesion layers. Phase evolution was observed to be unaffected by the adhesion layer. (111) oriented PZT films were obtained on all substrates and hence Ti diffusion from the adhesion layer appeared to have limited influence on texture control in these films. It is suggested that the (111) orientation of the perovskite phase is directly seeded by the Pt(111) texture.

  17. Factors controlling the microstructure of Ce0.9Gd0.1O2-δ films in pulsed laser deposition process

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, S.; Döbeli, M.;

    Films of Ce0.9Gd0.1O2-δ(CGO10) are prepared at a range of conditions by pulsed laser deposition (PLD) on a single crystal Si (100) and MgO (100), and on a polycrystalline Pt/MgO (100) substrate. The relationship between the film microstructure, crystallography, chemical composition and PLD...

  18. Metal nanostructures with complex surface morphology: The case of supported lumpy Pd and Pt nanoparticles produced by laser processing of metal films

    Science.gov (United States)

    Ruffino, F.; Maugeri, P.; Cacciato, G.; Zimbone, M.; Grimaldi, M. G.

    2016-09-01

    In this work we report on the formation of lumpy Pd and Pt nanoparticles on fluorine-doped tin oxide/glass (FTO/glass) substrate by a laser-based approach. In general, complex-surface morphology metal nanoparticles can be used in several technological applications exploiting the peculiarities of their physical properties as modulated by nanoscale morphology. For example plasmonic metal nanoparticles presenting a lumpy morphology (i.e. larger particles coated on the surface by smaller particles) can be used in plasmonic solar cell devices providing broadband scattering enhancement over the smooth nanoparticles leading, so, to the increase of the device efficiency. However, the use of plasmonic lumpy nanoparticles remains largely unexplored due to the lack of simply, versatile, low-cost and high-throughput methods for the controllable production of such nanostructures. Starting from these considerations, we report on the observation that nanoscale-thick Pd and Pt films (17.6 and 27.9 nm, 12.1 and 19.5 nm, respectively) deposited on FTO/glass surface irradiated by nanosecond pulsed laser at fluences E in the 0.5-1.5 J/cm2 range, produce Pd and Pt lumpy nanoparticles on the FTO surface. In addition, using scanning electron microscopy analyses, we report on the observation that starting from each metal film of fixed thickness h, the fraction F of lumpy nanoparticles increases with the laser fluence E and saturates at the higher fluences. For each fixed fluence, F was found higher starting from the Pt films (at each starting film thickness h) with respect to the Pd films. For each fixed metal and fluence, F was found to be higher decreasing the starting thickness of the deposited film. To explain the formation of the lumpy Pd and Pt nanoparticles and the behavior of F as a function of E and h both for Pd and Pt, the thermodynamic behavior of the Pd and Pt films and nanoparticles due to the interaction with the nanosecond laser is discussed. In particular, the

  19. Enhancement of L10 ordering with the c-axis perpendicular to the substrate in FePt alloy film by using an epitaxial cap-layer

    Science.gov (United States)

    Ohtake, Mitsuru; Nakamura, Masahiro; Futamoto, Masaaki; Kirino, Fumiyoshi; Inaba, Nobuyuki

    2017-05-01

    FePt alloy thin films with cap-layers of MgO or C are prepared on MgO(001) single-crystal substrates by using a two-step method consisting of low-temperature deposition at 200 °C followed by high-temperature annealing at 600 °C. The FePt film thickness is fixed at 10 nm, whereas the cap-layer thickness is varied from 1 to 10 nm. The influences of cap-layer material and cap-layer thickness on the variant structure and the L10 ordering are investigated. Single-crystal FePt(001) films with disordered fcc structure (A1) grow epitaxially on the substrates at 200 °C. Single-crystal MgO(001) cap-layers grow epitaxially on the FePt films, whereas the structure of C cap-layers is amorphous. The phase transformation from A1 to L10 occurs when the films are annealed at 600 °C. The FePt films with MgO cap-layers thicker than 2 nm consist of L10(001) variant with the c-axis perpendicular to the substrate surface, whereas those with C cap-layers involve small volumes of L10(100) and (010) variants with the c-axis lying in the film plane. The in-plane and the out-of-plane lattices are respectively more expanded and contracted in the continuous-lattice MgO/FePt/MgO structure due to accommodations of misfits of FePt film with respect to not only the MgO substrate but also the MgO cap-layer. The lattice deformation promotes phase transformation along the perpendicular direction and L10 ordering. The FePt films consisting of only L10(001) variant show strong perpendicular magnetic anisotropies and low in-plane coercivities. The present study shows that an introduction of epitaxial cap-layer is effective in controlling the c-axis perpendicular to the substrate surface.

  20. Characterization of copper selenide thin films deposited by chemical bath deposition technique

    Science.gov (United States)

    Al-Mamun; Islam, A. B. M. O.

    2004-11-01

    A low-cost chemical bath deposition (CBD) technique has been used for the preparation of Cu2-xSe thin films onto glass substrates and deposited films were characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and UV-vis spectrophotometry. Good quality thin films of smooth surface of copper selenide thin films were deposited using sodium selenosulfate as a source of selenide ions. The structural and optical behaviour of the films are discussed in the light of the observed data.

  1. Laser-induced in situ synthesis of Pd and Pt nanoparticles on polymer films

    Science.gov (United States)

    Mehrabanian, Mehran; Morselli, Davide; Caputo, Gianvito; Scarpellini, Alice; Palazon, Francisco; Athanassiou, Athanassia; Fragouli, Despina

    2016-12-01

    We present the localized in situ formation of Pd and Pt nanoparticles embedded in chitosan solid films. This is achieved by the photo-induced reduction of metallic precursors, previously incorporated in chitosan films, through controlled UV pulsed laser irradiation. Interestingly, at high number of laser pulses, Pd and Pt follow different formation pathways, contrary to their common photoreduction mechanism occurring at low irradiation pulses. Specifically, in the case of the Pd, a photofragmentation process takes place fracturing the previously formed nanoparticles into smaller ones; whereas in the case of Pt, the prolonged irradiation promotes the nanoparticles agglomeration. The combination of both precursors in a binary solid system results in the combined formation of both Pd and Pt nanoparticles in the polymer film upon laser irradiation. The herein reported approach is an efficient and precise tool to generate size- and density-controlled Pd and Pt nanoparticles in desired areas of polymeric films, rendering this method a potential candidate for the fabrication of flexible polymeric devices for gas-sensing or electro-catalysis applications.

  2. Nano-structure formation of Fe-Pt perpendicular magnetic recording media co-deposited with MgO, Al{sub 2}O{sub 3} and SiO{sub 2} additives

    Energy Technology Data Exchange (ETDEWEB)

    Safran, G. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences 1121 Budapest, Konkoly-Thege ut 29-33 (Hungary)]. E-mail: safran@mfa.kfki.hu; Suzuki, T. [Akita Research Institute of Advanced Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Ouchi, K. [Akita Research Institute of Advanced Technology (AIT), 4-21 Sanuki, Araya, Akita 010-1623 (Japan); Barna, P.B. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences 1121 Budapest, Konkoly-Thege ut 29-33 (Hungary); Radnoczi, G. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences 1121 Budapest, Konkoly-Thege ut 29-33 (Hungary)

    2006-02-21

    Perpendicular magnetic recording media samples were prepared by sputter deposition on sapphire with a layer sequence of MgO seed-layer/Cr under-layer/FeSi soft magnetic under-layer/MgO intermediate layer/FePt-oxide recording layer. The effects of MgO, Al{sub 2}O{sub 3} and SiO{sub 2} additives on the morphology and orientation of the FePt layer were investigated by transmission electron microscopy. The samples exhibited (001) orientation of the L1 FePt phase with the mutual orientations of sapphire substrate//MgO(100)[001]//Cr(100)[11-bar0]//FeSi(100)[11-bar0]//MgO(100) [001]//FePt(001)[100]. The morphology of the FePt films varied due to the co-deposited oxides: The FePt layers were continuous and segmented by stacking faults aligned at 54{sup o} to the surface. Films with SiO{sub 2} addition, beside the oriented columnar FePt grains, exhibited a fraction of misoriented crystallites due to random repeated nucleation. Al{sub 2}O{sub 3} addition resulted in a layered structure, i.e. an initial continuous epitaxial FePt layer covered by a secondary layer of FePt-Al{sub 2}O{sub 3} composite. Both components (FePt and MgO) of the MgO-added samples were grown epitaxially on the MgO intermediate layer, so that a nano-composite of intercalated (001) FePt and (001) MgO was formed. The revealed microstructures and formation mechanisms may facilitate the improvement of the structural and magnetic properties of the FePt-oxide composite perpendicular magnetic recording media.

  3. Work function mediated by deposition of ultrathin polar FeO on Pt(111)

    Science.gov (United States)

    Lu, Shuangzan; Qin, Zhihui; Guo, Qinmin; Cao, Gengyu

    2017-01-01

    Significant work function changes from bare Pt(111) surface to 1 monolayer and 2 monolayers of ultrathin iron oxide (FeO) films on it are investigated by means of scanning tunneling microscopy/spectroscopy (STM/STS). With FeO layer-by-layer growth, a continuous reduction of the work function along with the surface vacuum level (VL) shifting is observed. We found that the compression of the electron spill-out at the metal-oxide interface and the substantial reconstruction of 2 ML FeO film, respectively, make major contributions to the first and the second reductions of the work function. The rectifying effect in FeO films is also observed, which is attributed to the downward shift of band alignment imposed by the total change in surface dipole. Our work shows that the polar oxide films play an important role to adjust surface electronic structures for enhancing device functionality.

  4. ZnO thin films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tsoutsouva, M.G. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Papadimitriou, D. [National Technical University of Athens, Department of Physics, GR-15780 Athens (Greece); Fasaki, I.; Kompitsas, M. [Theor. and Phys./Chem. Institute, National Hellenic Research Foundation, 48 Vas. Konstantinou Ave., 11635 Athens (Greece)

    2011-04-15

    Zinc oxide (ZnO) thin films were deposited on soda lime glass substrates by pulsed laser deposition (PLD) in an oxygen-reactive atmosphere. The structural, optical, and electrical properties of the as-prepared thin films were studied in dependence of substrate temperature and oxygen pressure. High quality polycrystalline ZnO films with hexagonal wurtzite structure were deposited at substrate temperatures of 100 and 300 deg. C. The RMS roughness of the deposited oxide films was found to be in the range 2-9 nm and was only slightly dependent on substrate temperature and oxygen pressure. Electrical measurements indicated a decrease of film resistivity with the increase of substrate temperature and the decrease of oxygen pressure. The ZnO films exhibited high transmittance of 90% and their energy band gap and thickness were in the range 3.26-3.30 eV and 256-627 nm, respectively.

  5. Ion Beam Assisted Deposition Of Optical Thin Films - Recent Results

    Science.gov (United States)

    McNally, J. J.; Al-Jumaily, G. A.; Wilson, S. R.; McNeil, J. R.

    1985-11-01

    We have examined the properties of dielectric (Ti02, Si02, -Al203, Ta205 and Hf02) films deposited using ion-assisted deposition (IAD). The films were characterized using an angularly resolved scatterometer, spectrophotometer and Raman spectroscopy. A reduction in optical scatter, especially that due to low spatial frequencies, is observed for films deposited with simultaneous ion bombardment. Higher values of refractive index are obtained for films deposited using IAD. Raman spectra indicate a crystalline phase change in TiO2 films is induced by bombardment of samples with 02 ions during deposition. Other experimental data and the effects of the induced phase transition on the optical properties of TiO2 will be discussed.

  6. Critical Factors Controlling Pd and Pt Potential in Porphyry Cu–Au Deposits: Evidence from the Balkan Peninsula

    Directory of Open Access Journals (Sweden)

    Demetrios G. Eliopoulos

    2014-03-01

    Full Text Available Porphyry Cu–Au–Pd±Pt deposits are significant Au resources, but their Pd and Pt potential is still unknown. Elevated Pd, Pt (hundreds of ppb and Au contents are associated with typical stockwork magnetite-bornite-chalcopyrite assemblages, at the central parts of certain porphyry deposits. Unexpected high grade Cu–(Pd+Pt (up to 6 ppm mineralization with high Pd/Pt ratios at the Elatsite porphyry deposit, which is found in a spatial association with the Chelopech epithermal deposit (Bulgaria and the Skouries porphyry deposit, may have formed during late stages of an evolved hydrothermal system. Estimated Pd, Pt and Au potential for porphyry deposits is consistent with literature model calculations demonstrating the capacity of aqueous vapor and brine to scavenge sufficient quantities of Pt and Pd, and could contribute to the global platinum-group element (PGE production. Critical requirements controlling potential of porphyry deposits may be from the metals contained in magma (metasomatized asthenospheric mantle wedge as indicated by significant Cr, Co, Ni and Re contents. The Cr content may be an indicator for the mantle input.

  7. Solution deposition of nanometer scale silver films as an alternative to vapor deposition for plasmonic excitation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Derek S.; Sathish, R. Sai; Kostov, Yordan [Center for Advanced Sensor Technology and Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Rao, Govind, E-mail: grao@umbc.ed [Center for Advanced Sensor Technology and Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States)

    2010-05-03

    We report the attainment of surface plasmon-coupled emission (SPCE) from highly uniform thin silver films, solution-deposited on glass substrates by a wet chemistry approach. The surface morphology of these films was characterized by atomic force microscopy. The SPCE emission enhancements, polarization and angularity obtained from solution-deposited silver on BK7 glass were comparable to that achieved from conventional SPCE slides prepared via vapor deposition. This facile, wet chemistry procedure for the deposition of SPCE films provides an inexpensive, low maintenance alternative to vapor deposition for SPCE substrate preparation. This would allow the fluorescence observation technique to become more readily available for high sensitivity, low cost applications.

  8. Electric field control of magnetic anisotropy in a Co/Pt bilayer deposited on a high-κ SrTiO3

    Science.gov (United States)

    Nakazawa, S.; Obinata, A.; Chiba, D.; Ueno, K.

    2017-02-01

    The perpendicular magnetic anisotropy (PMA) of a Co (0.5 nm)/Pt (2.4 nm) bilayer film was electrostatically tuned using a high-κ dielectric, SrTiO3, with a back-gating configuration. The Co film was directly deposited onto a SrTiO3 (001) substrate and capped by a Pt layer. The coercivity was enhanced (reduced) by applying a positive (negative) gate bias. The efficiency of the PMA energy modulation by the electric field was determined to be 1300-23 100 fJ/V m, which is 1-3 orders of magnitude higher than the efficiencies obtained in previous studies. The superior efficiency of this system is most likely attributable to the large dielectric constant of the SrTiO3 gate insulator and could be evidence that the PMA energy modulation is induced by charge accumulation.

  9. Effect of Pt Concentration on the Grain Growth of TiO2sol-gel Films

    Directory of Open Access Journals (Sweden)

    Jia Y.J.

    2017-01-01

    Full Text Available Pt metallic has been supported on TiO2 surface using different methods, Here, Pt doped TiO2 (Pt-TiO2 sol gel thin film were successfully produced by reducing chloroplatinc acid (H2PtCl6. The structures of prepared composites were investigated using X-ray diffraction (XRD. The physical morphologies of the composites were examined using transmission electron microscope (TEM. The grain size of Pt-TiO2 thin film after annealing was also measured by atomic force microscope (AFM images.

  10. Bismuth thin films obtained by pulsed laser deposition

    Science.gov (United States)

    Flores, Teresa; Arronte, Miguel; Rodriguez, Eugenio; Ponce, Luis; Alonso, J. C.; Garcia, C.; Fernandez, M.; Haro, E.

    1999-07-01

    In the present work Bi thin films were obtained by Pulsed Laser Deposition, using Nd:YAG lasers. The films were characterized by optical microscopy. Raman spectroscopy and X-rays diffraction. It was accomplished the real time spectral emission characterization of the plasma generated during the laser evaporation process. Highly oriented thin films were obtained.

  11. Properties of electrophoretically deposited single wall carbon nanotube films

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Junyoung; Jalali, Maryam; Campbell, Stephen A., E-mail: campb001@umn.edu

    2015-08-31

    This paper describes techniques for rapidly producing a carbon nanotube thin film by electrophoretic deposition at room temperature and determines the film mass density and electrical/mechanical properties of such films. The mechanism of electrophoretic deposition of thin layers is explained with experimental data. Also, film thickness is measured as a function of time, electrical field and suspension concentration. We use Rutherford backscattering spectroscopy to determine the film mass density. Films created in this manner have a resistivity of 2.14 × 10{sup −3} Ω·cm, a mass density that varies with thickness from 0.12 to 0.54 g/cm{sup 3}, and a Young's modulus between 4.72 and 5.67 GPa. The latter was found to be independent of thickness from 77 to 134 nm. We also report on fabricating free-standing films by removing the metal seed layer under the CNT film, and selectively etching a sacrificial layer. This method could be extended to flexible photovoltaic devices or high frequency RF MEMS devices. - Highlights: • We explain the electrophoretic deposition process and mechanism of thin SWCNT film deposition. • Characterization of the SWCNT film properties including density, resistivity, transmittance, and Young's modulus. • The film density and resistivity are found to be a function of the film thickness. • Techniques developed to create free standing layers of SW-CNTs for flexible electronics and mechanical actuators.

  12. Influence of deposition time on the properties of chemical bath deposited manganese sulfide thin films

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-12-01

    Full Text Available Manganese sulfide thin films were chemically deposited from an aqueous solution containing manganese sulfate, sodium thiosulfate and sodium tartrate. The influence of deposition time (2, 3, 6 and 8 days on the properties of thin films was investigated. The structure and surface morphology of the thin films were studied by X-ray diffraction and atomic force microscopy, respectively. In addition, in order to investigate the optical properties of the thin films, the UV-visible spectrophotometry was used. The XRD results indicated that the deposited MnS2 thin films exhibited a polycrystalline cubic structure. The number of MnS2 peaks on the XRD patterns initially increased from three to six peaks and then decreased to five peaks, as the deposition time was increased from 2 to 8 days. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the deposition time.

  13. Plasma-deposited a-C(N) H films

    CERN Document Server

    Franceschini, D E

    2000-01-01

    The growth behaviour, film structure and mechanical properties of plasma-deposited amorphous hydrogenated carbon-nitrogen films are shortly reviewed. The effect of nitrogen-containing gas addition to the deposition to the hydrocarbon atmospheres used is discussed, considering the modifications observed in the chemical composition growth kinetics, carbon atom hybridisation and chemical bonding arrangements of a-C(N):H films. The overall structure behaviour is correlated to the variation of the mechanical properties.

  14. Production and characterization of titanium (Ti), platinum (Pt) and tantalum (Ta) thin films for native DNA biosensors

    Science.gov (United States)

    Genç, Eminegül; Kepceoǧlu, Abdullah; Gezgin, Serap Yiǧit; Kars, Meltem Demirel; Kılıç, Hamdi Şükür

    2017-02-01

    The use of the femtosecond (fs) laser pulses for ablation applications have several advantageous and Laser-Induced Forward Transfer (LIFT) is an ablation-driven transfer process. The use of fs laser pulses for LIFT is gaining a great attraction nowadays. The most of the Direct Writing (DW) methods are laser based techniques and the LIFT technique is the one of them. This spectacular technique allows high resolution without lithographic processes. In this study, we have grown Ti, Pt and Ta thin films on the microscope slides by Pulse Laser Deposition (PLD) technique using Nd:YAG laser in the high vacuum condition. As a result, thin films produced in this work is a good candidate to produce native DNA biosensors based on LIFT technique.

  15. Deposition of copper selenide thin films and nanoparticles

    Science.gov (United States)

    Hu, Yunxiang; Afzaal, Mohammad; Malik, Mohammad A.; O'Brien, Paul

    2006-12-01

    A new method is reported for the growth of copper selenide thin films and nanoparticles using copper acetylacetonate and trioctylphosphine selenide. Aerosol-assisted chemical vapor deposition experiments lead to successful deposition of tetragonal Cu 2Se films. In contrast, hexadecylamine capped nanoparticles are composed of cubic Cu 2-xSe. The deposited materials are optically and structurally characterized. The results of this comprehensive study are described and discussed.

  16. (001)-textured growth of L1{sub 0}-FePt thin films on MgO and Cr seed layers

    Energy Technology Data Exchange (ETDEWEB)

    Matthes, Patrick; Brombacher, Christoph; Daniel, Marcus; Beddies, Gunther; Albrecht, Manfred [Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz (Germany)

    2011-07-01

    Chemically ordered FePt has a high uniaxial anisotropy with the easy axis in (001)-direction. It has been shown that (001)-textured MgO and Cr [2] seed layers can be used to stabilize the (001)-texture of L1{sub 0}-chemically ordered FePt on amorphous substrates. In this study the growth of MgO and Cr seed layers was optimized by varying the process parameters (deposition temperature and rate as well as Ar pressure) and their influence on the magnetic properties of epitaxially grown FePt films have been analyzed. In addition, reference samples on MgO(100) single crystals were prepared. XRD measurements revealed a high degree of chemical order leading to a K{sub eff} of (8.5{+-}1.3) x 10{sup 6}erg/cm{sup 3} after FePt deposition at 350 C. The low deposition temperature results in a smooth film morphology and a reversal behaviour which is dominated by domain wall propagation.

  17. Influence of deposition temperature on ionic conductivity of perovskite (Li0.5 La0.5) TiO3 solid state electrolyte thin film

    Institute of Scientific and Technical Information of China (English)

    SHEN; Wan; YANG; Zhi-min; XING; Guang-jian; MAO; Chang-hui; DU; Jun

    2005-01-01

    Thin film microbattery is a promising micropower source for its high energy density and good cell performances, and the application of fast lithium ion conducting solids as electrolytes is thus very important. (Li0.5 La0.5 )TiO3 (LLTO) thin film electrolytes for thin film microbattery were prepared onto Pt/Si substrates using magnetron sputtering. As-deposited LLTO thin films showed amorphous-like phases and when deposition temperature increases the ionic conductivity raises accordingly. The ionic conductivity of LLTO thin film reaches 8. 7 × 10-6 S/cm when the deposition temperature is 400℃, which shows that the LLTO thin films deposited by magnetron sputtering are suitable for application as an electrolyte for thin film microbattery.

  18. In situ STM imaging of bis-3-sodiumsulfopropyl-disulfide molecules adsorbed on copper film electrodeposited on Pt(111) single crystal electrode.

    Science.gov (United States)

    Tu, HsinLing; Yen, PoYu; Chen, Sihzih; Yau, ShuehLin; Dow, Wei-Ping; Lee, Yuh-Lang

    2011-06-07

    The adsorption of bis-3-sodiumsulfopropyldi-sulfide (SPS) on metal electrodes in chloride-containing media has been intensively studied to unveil its accelerating effect on Cu electrodeposition. Molecular resolution scanning tunneling microscopy (STM) imaging technique was used in this study to explore the adsorption and decomposition of SPS molecules concurring with the electrodeposition of copper on an ordered Pt(111) electrode in 0.1 M HClO(4) + 1 mM Cu(ClO(4))(2) + 1 mM KCl. Depending on the potential of Pt(111), SPS molecules could react, adsorb, and decompose at chloride-capped Cu films. A submonolayer of Cu adatoms classified as the underpotential deposition (UPD) layer at 0.4 V (vs Ag/AgCl) was completely displaced by SPS molecules, possibly occurring via RSSR (SPS) + Cl-Cu-Pt → RS(-)-Pt(+) + RS(-) (MPS) + Cu(2+) + Cl(-), where MPS is 3-mercaptopropanesulfonate. By contrast, at 0.2 V, where a full monolayer of Cu was presumed to be deposited, SPS molecules were adsorbed in local (4 × 4) structures at the lower ends of step ledges. Bulk Cu deposition driven by a small overpotential (η deposit at the very beginning (deposit, the chloride adlayer was still adsorbed to afford SPS admolecules arranged in a unique 1D striped phase. SPS molecules could decompose into MPS upon further Cu deposition, as a (2 × 2)-MPS structure was observed with prolonged in situ STM imaging. It was possible to visualize either SPS admolecules in the upper plane or chloride adlayer sitting underneath upon switching the imaging conditions. Overall, this study established a MPS molecular film adsorbed to the chloride adlayer sitting atop the Cu deposit.

  19. Electron Induced Surface Reactions of cis-Pt(CO)2Cl2: A Route to Focused Electron Beam Induced Deposition of Pure Pt Nanostructures.

    Science.gov (United States)

    Spencer, Julie A; Wu, Yung-Chien; McElwee-White, Lisa; Fairbrother, D Howard

    2016-07-27

    Using mechanistic data from surface science studies on electron-induced reactions of organometallic precursors, cis-Pt(CO)2Cl2 (1) was designed specifically for use in focused electron beam induced deposition (FEBID) of Pt nanostructures. Electron induced decomposition of adsorbed 1 under ultrahigh vacuum (UHV) conditions proceeds through initial CO loss as determined by in situ X-ray photoelectron spectroscopy and mass spectrometry. Although the Pt-Cl bonds remain intact during the initial decomposition step, larger electron doses induce removal of the residual chloride through an electron-stimulated desorption process. FEBID structures created from cis-Pt(CO)2Cl2 under steady state deposition conditions in an Auger spectrometer were determined to be PtCl2, free of carbon and oxygen. Coupled with the electron stimulated removal of chlorine demonstrated in the UHV experiments, the Auger deposition data establish a route to FEBID of pure Pt. Results from this study demonstrate that structure-activity relationships can be used to design new precursors specifically for FEBID.

  20. Synthesis of nanostructured lean-NO x catalysts by direct laser deposition of monometallic Pt-, Rh- and bimetallic PtRh-nanoparticles on SiO2 support

    Science.gov (United States)

    Savastenko, N.; Volpp, H.-R.; Gerlach, O.; Strehlau, W.

    2008-02-01

    Monometallic Pt and Rh and bimetallic PtRh catalysts with a highly dispersed noble metal weight loading of ca. 1 wt% were produced via the direct deposition of nanoparticles on different SiO2 supports by means of pulsed ultra-violet (248 nm) excimer laser ablation of Pt, Rh bulk metal and PtRh alloy targets. Backscattered electron microscopy (BSE), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) were employed to characterize the deposited nanoparticles, which were found to exhibit narrow size distribution centred around 2.5 nm. The catalytic activities for lean NO x reduction of the monometallic and bimetallic catalyst samples were investigated in a flow reactor setup in the temperature range 100-400°C using a test gas mixture representative of oxygen rich diesel engine exhaust gas. For comparison a Rh/SiO2 reference catalyst prepared by a conventional impregnation method was also tested. Further experiments were performed in which PtRh nanoparticles were deposited on a Rh/SiO2 reference catalyst sample to study the possibility for controlled modification of its activity. The catalytic activity measurements revealed that among the samples solely prepared by laser deposition the PtRh-SiO2 nanoparticle catalyst showed the highest activity for NO x reduction at low temperatures 100-300°C. In addition, it could be demonstrated that the initially low NO x reduction activity and the N2 selectivity of the Rh/SiO2 reference catalyst sample for temperatures below 250°C can be enhanced by post laser deposition of PtRh nanoparticles.

  1. Effects of deposition time in chemically deposited ZnS films in acidic solution

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

    2015-08-31

    We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

  2. Spatial atomic layer deposition of zinc oxide thin films

    NARCIS (Netherlands)

    Illiberi, A.; Roozeboom, F.; Poodt, P.W.G.

    2012-01-01

    Zinc oxide thin films have been deposited at high growth rates (up to ~1 nm/s) by spatial atomic layer deposition technique at atmospheric pressure. Water has been used as oxidant for diethylzinc (DEZ) at deposition temperatures between 75 and 250 °C. The electrical, structural (crystallinity and mo

  3. Piezoelectric ceramic thick films deposited on silicon substrates by screen printing

    Science.gov (United States)

    Yao, Kui; He, Xujiang; Xu, Yuan; Chen, Meima

    2004-07-01

    Screen-printing processes offer advantages in producing directly patterned and integrated piezoelectric elements, and fill an important technological gap between thin film and bulk ceramics. However, several existing problems in the screen-printed piezoelectric thick films, such as the poor reliability and the required high sintering temperature, are significantly limiting their applications. In this work, lead zirconate titanate (PZT) ceramic films of 30 μm in thickness were deposited on Pt-coated silicon substrates by the screen-printing process, in which the ceramic pastes were prepared through a chemical liquid-phase doping approach. Porous thick films with good adhesion were formed on the substrates at a temperature of 925°C. Stable out-of-plane piezoelectric vibration of the thick films was observed with a laser scanning vibrometer (LSV), and the piezoelectric dilatation magnitude was determined accordingly. Our piezoelectric measurements through the areal displacement detection with LSV exhibited distinct advantages for piezoelectric film characterization, including high reliability, high efficiency, and comprehensive information. The longitudinal piezoelectric coefficients of the thick films were calculated from the measured dilatation data through a numerical simulation. High piezoelectric voltage constants were obtained due to the very low dielectric constant of the porous thick films. The application potentials of our screen-printed thick films as integrated piezoelectric sensors are discussed.

  4. Electrochemical deposition of copper onto Pt(111) in the presence of (bi)sulfate anions

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, C.A. [Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)]|[Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool, L69 7ZE (United Kingdom); Markovic, N.M.; Ross, P.N. [Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

    1997-08-01

    Using {ital in situ} x-ray diffraction we have studied the underpotential deposition (UPD) of copper onto a Pt(111) electrode in sulfuric acid. Deposition occurs in a two-stage process; close to a full monolayer of Cu being preceded by a ({radical}(3){times}{radical}(3))R30{degree} structure that consists of both Cu and (bi)sulfate anions and is similar to the structure observed on the Au(111) electrode. Utilizing anomalous scattering methods we can accurately determine the Cu coverage during UPD and propose structural models based on crystal truncation rod measurements. {copyright} {ital 1997} {ital The American Physical Society}

  5. Enhanced spin Hall ratios by Al and Hf impurities in Pt thin films

    Science.gov (United States)

    Nguyen, Minh-Hai; Zhao, Mengnan; Ralph, Daniel C.; Buhrman, Robert A.

    The spin Hall effect (SHE) in Pt has been reported to be strong and hence promising for spintronic applications. In the intrinsic SHE mechanism, which has been shown to be dominant in Pt, the spin Hall conductivity σSH is constant, dependent only on the band structure of the spin Hall material. The spin Hall ratio θSH =σSH . ρ , on the other hand, should be proportional to the electrical resistivity ρ of the spin Hall layer. This suggests the possibility of enhancing the spin Hall ratio by introducing additional diffusive scattering to increase the electrical resistivity of the spin Hall layer. Our previous work has shown that this could be done by increasing the surface scattering by growing thinner Pt films in contact with higher resistivity materials such as Ta. In this talk, we discuss another approach: to introduce impurities of metals with negligible spin orbit torque into the Pt film. Our PtAl and PtHf alloy samples exhibit strong enhancement of the spin Hall torque efficiency with impurity concentration due to increased electrical resistivity. Supported in part by Samsung Electronics.

  6. High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

    Directory of Open Access Journals (Sweden)

    Anabil Gayen

    2013-01-01

    Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

  7. Fabrication of Supported AuPt Alloy Nanocrystals with Enhanced Electrocatalytic Activity for Formic Acid Oxidation through Conversion Chemistry of Layer-Deposited Pt(2+) on Au Nanocrystals.

    Science.gov (United States)

    Kim, Seong Hyeon; Jeong, Hwakyeung; Kim, Jongwon; Lee, In Su

    2015-10-07

    The exploitation of nanoconfined conversion of Au- and Pt-containing binary nanocrystals for developing a controllable synthesis of surfactant-free AuPt nanocrystals with enhanced formic acid oxidation (FAO) activity is reported, which can be stably and evenly immobilized on various support materials to diversify and optimize their electrocatalytic performance. In this study, an atomic layer of Pt(2+) species is discovered to be spontaneously deposited in situ on the Au nanocrystal generated from a reverse-microemulsion solution. The resulting Au/Pt(2+) nanocrystal thermally transforms into a reduced AuPt alloy nanocrystal during the subsequent solid-state conversion process within the SiO2 nanosphere. The alloy nanocrystals can be isolated from SiO2 in a surfactant-free form and then dispersedly loaded on the carbon sphere surface, allowing for the production of a supported electrocatalyst that exhibits much higher FAO activity than commercial Pt/C catalysts. Furthermore, by involving Fe3O4 nanocrystals in the conversion process, the AuPt alloy nanocrystals can be grown on the oxide surface, improving the durability of supported metal catalysts, and then uniformly loaded on a reduced graphene oxide (RGO) layer with high electroconductivity. This produces electrocatalytic AuPt/Fe3O4/RGO nanocomposites whose catalyst-oxide-graphene triple-junction structure provides improved electrocatalytic properties in terms of both activity and durability in catalyzing FAO. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Characterization of Pb(Zr, Ti)O sub 3 thin films prepared by metal-organic chemical-vapor deposition using a solid delivery system

    CERN Document Server

    Shin, J C; Hwang, C S; Kim, H J; Lee, J M

    1999-01-01

    Pb(Zr, Ti)O sub 3 (PZT) thin films were deposited on Pt/SiO sub 2 /Si substrates by metal-organic chemical-vapor deposition technique using a solid delivery system to improve the reproducibility of the deposition. The self-regulation mechanism, controlling the Pb-content of the film, was observed to work above a substrate temperature of 620 .deg. C. Even with the self-regulation mechanism, PZT films having low leakage current were obtained only when the molar mixing ratio of the input precursors was 1Pt/PZT/Pt capacitor was Schottky emission with a barrier height of 1.36 eV.

  9. Growth of Pt thin films on Cu(111) and formation of Pt/Cu surface alloys: growth mechanism and diffusion barrier

    CERN Document Server

    Boo, J H; Lee, S B; Kwak, H T; Schröder, U; Linke, R; Wandelt, K

    1999-01-01

    Ultra-thin-platinum films evaporated on Cu(111) at 100 K and at room temperature were investigated by using in situ Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). A growth mechanism of the layer-by layer type was evidenced up to at least 5-ML of Pt. Over the first Pt monolayer, the Pt-Pt bond distances were strained about 7 % beyond the equilibrium bond distances found for bulk platinum. Surface alloys were formed by diffusing the Pt adatoms into the Cu(111) substrate at temperatures above 500 K with a diffusion barrier of 0.85 eV. For higher annealing temperatures, the Pt concentration got smaller. From an Auger depth profile, the diffusion barrier for surface alloy formation was estimated using Fick's second law.

  10. SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

    Science.gov (United States)

    Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

    2016-05-01

    The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

  11. Interfacial reaction and electrical properties of HfO2 film gate dielectric prepared by pulsed laser deposition in nitrogen: role of rapid thermal annealing and gate electrode.

    Science.gov (United States)

    Wang, Yi; Wang, Hao; Ye, Cong; Zhang, Jun; Wang, Hanbin; Jiang, Yong

    2011-10-01

    The high-k dielectric HfO(2) thin films were deposited by pulsed laser deposition in nitrogen atmosphere. Rapid thermal annealing effect on film surface roughness, structure and electrical properties of HfO(2) film was investigated. The mechanism of interfacial reaction and the annealing atmosphere effect on the interfacial layer thickness were discussed. The sample annealed in nitrogen shows an amorphous dominated structure and the lowest leakage current density. Capacitors with high-k HfO(2) film as gate dielectric were fabricated, using Pt, Au, and Ti as the top gate electrode whereas Pt constitutes the bottom side electrode. At the gate injection case, the Pt- and Au-gated metal oxide semiconductor devices present a lower leakage current than that of the Ti-gated device, as well as similar leakage current conduction mechanism and interfacial properties at the metal/HfO(2) interface, because of their close work function and chemical properties.

  12. Crystalline Indium Sulphide thin film by photo accelerated deposition technique

    Science.gov (United States)

    Dhanya, A. C.; Preetha, K. C.; Deepa, K.; Remadevi, T. L.

    2015-02-01

    Indium sulfide thin films deserve special attention because of its potential application as buffer layers in CIGS based solar cells. Highly transparent indium sulfide (InS) thin films were prepared using a novel method called photo accelerated chemical deposition (PCD). Ultraviolet source of 150 W was used to irradiate the solution. Compared to all other chemical methods, PCD scores its advantage for its low cost, flexible substrate and capable of large area of deposition. Reports on deposition of high quality InS thin films at room temperature are very rare in literature. The precursor solution was initially heated to 90°C for ten minutes and then deposition was carried out at room temperature for two hours. The appearance of the film changed from lemon yellow to bright yellow as the deposition time increased. The sample was characterized for its structural and optical properties. XRD profile showed the polycrystalline behavior of the film with mixed phases having crystallite size of 17 nm. The surface morphology of the films exhibited uniformly distributed honey comb like structures. The film appeared to be smooth and the value of extinction coefficient was negligible. Optical measurements showed that the film has more than 80% transmission in the visible region. The direct band gap energy was 2.47eV. This method is highly suitable for the synthesis of crystalline and transparent indium sulfide thin films and can be used for various photo voltaic applications.

  13. Nanocrystalline Diamond Films Deposited by Electron Assisted Hot Filament Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nanocrystalline diamond films were deposited on polished Si wafer surface with electron assisted hot filament chemical vapor deposition at 1 kPa gas pressure, the deposited films were characterized and observed by Raman spectrum, X-ray diffraction, atomic force microscopy and semiconductor characterization system. The results show that when 8 A bias current is applied for 5 h, the surface roughness decreases to 28.5 nm. After 6 and 8 A bias current are applied for 1 h, and the nanocrystalline films deposition continue for 4 h with 0 A bias current at 1 kPa gas pressure. The nanocrystalline diamond films with 0.5×109 and 1×1010 Ω·cm resistivity respectively are obtained. It is demonstrated that electron bombardment plays an important role of nucleation to deposit diamond films with smooth surface and high resistivity.

  14. PMN-PT-PZT composite films for high frequency ultrasonic transducer applications.

    Science.gov (United States)

    Hsu, Hsiu-Sheng; Benjauthrit, Vatcharee; Zheng, Fan; Chen, Rumin; Huang, Yuhong; Zhou, Qifa; Shung, K Kirk

    2012-06-01

    We have successfully fabricated x(0.65PMN-0.35PT)-(1 - x)PZT (xPMN-PT-(1 - x)PZT), where x is 0.1, 0.3, 0.5, 0.7 and 0.9, thick films with a thickness of approximately 9 µm on platinized silicon substrate by employing a composite sol-gel technique. X-ray diffraction analysis and scanning electron microscopy revealed that these films are dense and creak-free with well-crystallized perovskite phase in the whole composition range. The dielectric constant can be controllably adjusted by using different compositions. Higher PZT content of xPMN-PT-(1 - x)PZT films show better ferroelectric properties. A representative 0.9PMN-PT-0.1PZT thick film transducer is built. It has 200 MHz center frequency with a -6 dB bandwidth of 38% (76 MHz). The measured two-way insertion loss is 65 dB.

  15. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

    KAUST Repository

    Biausque, Gregory

    2015-04-28

    Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

  16. Sputtering deposition and characterization of ultrathin amorphous carbon films

    Science.gov (United States)

    Lu, Wei

    1999-11-01

    This dissertation focuses on experimental investigations of ultrathin, ultrasmooth amorphous carbon (a-C) films deposited on Si(100) substrates by radio frequency (RF) sputtering and characterization of the nanomechanical and nanotribological properties and thermal stability of the films. Ultrathin a-C films of thickness 5--100 nm and typical root-mean-square roughness of 0.15--1 nm were deposited on ultrasmooth Si(100) substrates using pure argon as the sputtering gas. A low-pressure RF argon discharge model was used to analyze the plasma parameters in the film growth environment. These plasma parameters correlate the deposition conditions with the film growth processes. Atomic force microscopy (AFM) and surface force microscopy (SFM) were used to characterize the nanomechanical and nanotribological properties of the a-C films. X-ray photoelectron spectroscopy (XPS) was used to investigate the compositions and microstructures of the films. Sputter-etching measurements of the a-C films by energetic argon ion bombardment were used to study the surface binding energy of carbon atoms in a-C films deposited under different conditions. The dependence of film properties on deposition conditions was studied, and relations between nanomechanical and nanotribological properties were discussed in terms of a modified deformation index. The deformation and nanotribology mechanisms of the a-C films were compared with those of other films, such as TiC and Cr films (both 100 nm thick), and bulk Si(100). Reactive RF sputtering of nitrogenated amorphous carbon (a-CNx) films was investigated by introducing nitrogen into the a-C films during film growth by using an argon-nitrogen gas mixture as the sputtering gas. The alloying effect of nitrogen on the film growth and properties, such as hardness and surface energy, was studied and interpreted in terms of the changes in the plasma environment induced due to differences in the composition of the sputtering gas mixture. The thermal

  17. Iridium thin films deposited via pulsed laser deposition for future applications as transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Galeazzi, M. E-mail: galeazzi@physics.miami.edu; Chen, C.; Cohn, J.L.; Gundersen, J.O

    2004-03-11

    The University of Miami has recently started developing and studying high-resolution microcalorimeters operating near 100 mK for X-ray and particle physics and astrophysics. These detectors will be based on Transition Edge Sensors technology fabricated using iridium thin films deposited via the Pulsed Laser Deposition technique. We report here the preliminary result of the room temperature characterization of the Ir thin films, and an overview of future plans to use the films as transition edge sensors.

  18. Patterning of platinum (Pt) thin films by chemical wet etching in Aqua Regia

    Science.gov (United States)

    Köllensperger, P. A.; Karl, W. J.; Ahmad, M. M.; Pike, W. T.; Green, M.

    2012-06-01

    The chemical and physical properties of platinum (Pt) make it a useful material for microelectromechanical systems and microfluidic applications such as lab-on-a-chip devices. Platinum thin-films are frequently employed in applications where electrodes with high chemical stability, low electrical resistance or a high melting point are needed. Due to its chemical inertness it is however also one of the most difficult metals to pattern. The gold standard for patterning is chlorine RIE etching, a capital-intensive process not available in all labs. Here we present simple fabrication protocols for wet etching Pt thin-films in hot Aqua Regia based on sputtered Ti/Pt/Cr and Cr/Pt/Cr metal multilayers. Chromium (Cr) or titanium (Ti) is used as an adhesion layer for the Pt. Cr is used as a hard masking layer during the Pt etch as it can be easily and accurately patterned with photoresist and withstands the Aqua Regia. The Cr pattern is transferred into the Pt and the Cr mask later removed. Only standard chemicals and cleanroom equipment/tools are required. Prior to the Aqua Regia etch any surface passivation on the Pt is needs to be removed. This is usually achieved by a quick dip in dilute hydrofluoric acid (HF). HF is usually also used for wet-etching the Ti adhesion layer. We avoid the use of HF for both steps by replacing the HF-dip with an argon (Ar) plasma treatment and etching the Ti layer with a hydrogen peroxide (H2O2) based etchant.

  19. Methanol Adsorption and Reaction on Samaria Thin Films on Pt(111

    Directory of Open Access Journals (Sweden)

    Jin-Hao Jhang

    2015-09-01

    Full Text Available We investigated the adsorption and reaction of methanol on continuous and discontinuous films of samarium oxide (SmOx grown on Pt(111 in ultrahigh vacuum. The methanol decomposition was studied by temperature programmed desorption (TPD and infrared reflection absorption spectroscopy (IRRAS, while structural changes of the oxide surface were monitored by low-energy electron diffraction (LEED. Methanol dehydrogenates to adsorbed methoxy species on both the continuous and discontinuous SmOx films, eventually leading to the desorption of CO and H2 which desorbs at temperatures in the range 400–600 K. Small quantities of CO2 are also detected mainly on as-prepared Sm2O3 thin films, but the production of CO2 is limited during repeated TPD runs. The discontinuous film exhibits the highest reactivity compared to the continuous film and the Pt(111 substrate. The reactivity of methanol on reduced and reoxidized films was also investigated, revealing how SmOx structures influence the chemical behavior. Over repeated TPD experiments, a SmOx structural/chemical equilibrium condition is found which can be approached either from oxidized or reduced films. We also observed hydrogen absence in TPD which indicates that hydrogen is stored either in SmOx films or as OH groups on the SmOx surfaces.

  20. Polythiophene thin films electrochemically deposited on sol-gel based TiO{sub 2} for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Valaski, R. [Divisao de Metrologia de Materiais (DIMAT), INMETRO, Xerem-Duque de Caxias, RJ 25250 (Brazil); Yamamoto, N.A.D.; Canestraro, C.D. [Departamento de Fisica, Universidade Federal do Parana, C. Postal 19044, 81531-990, Curitiba, PR (Brazil); Micaroni, L.; Mello, R.M.Q. [Departamento de Quimica, Universidade Federal do Parana, C. Postal 19081, 81531-990, Curitiba, PR (Brazil); Quirino, W.G.; Legani, C.; Achete, C.A. [Divisao de Metrologia de Materiais (DIMAT), INMETRO, Xerem-Duque de Caxias, RJ 25250 (Brazil); Roman, L.S. [Departamento de Fisica, Universidade Federal do Parana, C. Postal 19044, 81531-990, Curitiba, PR (Brazil); Cremona, M., E-mail: cremona@fis.puc-rio.b [Divisao de Metrologia de Materiais (DIMAT), INMETRO, Xerem-Duque de Caxias, RJ 25250 (Brazil); Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22453-970, RJ (Brazil)

    2010-12-30

    In this work, the influence of titanium dioxide (TiO{sub 2}) thin films on the efficiency of organic photovoltaic devices based on electrochemically synthesized polythiophene (PT) was investigated. TiO{sub 2} films were produced by sol-gel methods with controlled thickness. The best TiO{sub 2} annealing condition was determined through the investigation of the temperature influence on the electron charge mobility and resistivity in a range between 723 K and 923 K. The PT films were produced by chronoamperometric method in a 3-electrode cell under a controlled atmosphere. High quality PT films were produced onto 40 nm thick TiO{sub 2} layer previously deposited onto fluorine doped tin oxide (FTO) substrate. The morphology of PT films grown on both substrates and its strong influence on the device performance and PT minimum thickness were also investigated. The maximum external quantum efficiency (IPCE) reached was 9% under monochromatic irradiation ({lambda} = 610 nm; 1 W/m{sup 2}) that is three orders of magnitude higher than that presented by PT-homolayer devices with similar PT thickness. In addition, the open-circuit voltage (V{sub oc}) was about 700 mV and the short-circuit current density (J{sub sc}) was 0.03 A/m{sup 2} ({lambda} = 610 nm; 7 W/m{sup 2}). However, as for the PT-homolayer also the TiO{sub 2}/PT based devices are characterized by antibatic response when illuminated through FTO. Finally, the Fill Factor (FF) of these devices is low (25%), indicating that the series resistance (R{sub s}), which is strongly dependent of the PT thickness, is too large. This large R{sub s} value is compensated by TiO{sub 2}/PT interface morphology and by FTO/TiO{sub 2} and TiO{sub 2}/PT interface phenomena producing preferential paths in which the internal electrical field is higher, improving the device efficiency.

  1. Electrical Field Effects in Phthalocyanine Film Growth by Vapor Deposition

    Science.gov (United States)

    Banks, Curtis E.; Zhu, Shen; Frazier, Donald O.; Penn, Benjamin; Abdeldayem, Hossin; Hicks, Roslin; Sarkisov, Sergey

    1999-01-01

    Phthalocyanine, an organic material, is a very good candidate for non-linear optical application, such as high-speed switching and optical storage devices. Phthalocyanine films have been synthesized by vapor deposition on quartz substrates. Some substrates were coated with a very thin gold film for introducing electrical field. These films have been characterized by surface morphology, material structure, chemical and thermal stability, non-linear optical parameters, and electrical behaviors. The films have excellent chemical and optical stability. However, the surface of these films grown without electrical field shows flower-like morphology. When films are deposited under an electrical field ( an aligned structure is revealed on the surface. A comparison of the optical and electrical properties and the growth mechanism for these films grown with and without an electrical field will be discussed.

  2. Characterization and Electrical Properties of TiO2 Thin Films Deposited by Pulsed Laser Deposition

    Science.gov (United States)

    Badar, Nurhanna; Kamarulzaman, Norlida

    2011-12-01

    Thin film technology is very important in today's high-tech industry. TiO2 is a high-k dielectric material. Problems with thin film deposition arise when the thickness of the thin layers approaches a few hundred nm to less than 100 nm. High quality thin films within these dimensions are difficult to obtain. Issues of adhesion, crystal mismatch, crystal orientation, surface roughness, densification, etc. are problems that need to be addressed if good quality thin films for devices are to be fabricated. These factors have a relation with the thin film technique used. As an example, spin coating technique may be a cheaper technique but may not result in dense and very smooth surfaces. Pulsed LASER deposition (PLD) is a relatively newer method used in thin film fabrication. The advantages of PLD are, capability of very thin films being deposited on different types of substrates (up to monolayers), control of crystal orientation, capability of depositing materials with complex stoichiometry and ease of methodology with high throughput. This has industrial implications as a good method for thin film preparation. This work involves the deposition of TiO2 thin films using different deposition parameters and chamber environments.

  3. Magnetron sputtering deposition of [FePt/Ag]n multilayers for perpendicular recording

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    [FePt/Ag]n multilayers were deposited on glass substrates by RF magnetron sputtering and ex situ annealed at 550℃ for 30 min. The effects of inserted Ag layer thickness and the number of bilayer repetitions (n) on the structure and magnetic properties of the multilayers were investigated. It was found that the difference between in-plane and out-of-plane coercivities varied with an increase of inserted Ag layer thickness in the [FePt 2 nm/Ag x nm]10 multilayers. The ratio of out-of-plane coercivity to in-plane coercivity reached the maximum value with the Ag layer thickness of 5 nm, indicating that the Ag layer thickness plays an important role in obtaining perpendicular orientation. For the [FePt 2 nm/Ag 5 nm]n multilayers, perpendicular orientation is also influenced by n. The maximum value of the ratio of out-of-plane coercivity to in-plane coercivity appeared when n was given as 8. It was found that the [FePt 2 nm/Ag 5 nm]8 had a high perpendicular coercivity of 520 kA/m and a low in-plane one of 88 kA/m, which shows a strong perpendicular anisotropy.

  4. Thickness limit in perpendicular magnetic anisotropy L1{sub 0} FePt(0 0 1) thin film

    Energy Technology Data Exchange (ETDEWEB)

    Sun, A.-C. [Department of Physics and Center for Nanostorage Research, National Taiwan University, Taipei 106, Taiwan (China); Hsu, J.-H. [Department of Physics and Center for Nanostorage Research, National Taiwan University, Taipei 106, Taiwan (China)]. E-mail: jhhsu@phys.ntu.edu.tw; Kuo, P.C. [Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China); Huang, H.L. [Department of Physics and Center for Nanostorage Research, National Taiwan University, Taipei 106, Taiwan (China); Lu, H.C. [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Wang, S.F. [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China)

    2007-03-15

    Perpendicular magnetic anisotropy L1{sub 0} FePt (0 0 1) films with various thicknesses were prepared onto Pt(0 0 1)/Cr(0 0 2) bilayers. When the thickness of FePt layer was smaller than 30 nm, a single orientation of L1{sub 0} FePt(0 0 1) texture was present, confirming that the easy axis was perpendicular to the film plane. But as the thickness increased over 30 nm along with the L1{sub 0} FePt(0 0 1) orientation, the peak corresponding to L1{sub 0} FePt (1 1 1) orientation was also observed, which indicated the quality degradation of perpendicular magnetic anisotropy. From our study, the critical thickness for growing perfect L1{sub 0} FePt(0 0 1) single orientation is around 30 nm.

  5. Highly (1 1 1)-oriented and pyrochlore-free PMN-PT thin films derived from a modified sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Feng, M. [Institute for Advanced Ceramics, Department of Materials Science and Engineering, Harbin Institute of Technology, No. 92, West Da-Zhi Street, Heilongjiang, Harbin 150001 (China); Wang, W., E-mail: wangwen@hit.edu.c [Institute for Advanced Ceramics, Department of Materials Science and Engineering, Harbin Institute of Technology, No. 92, West Da-Zhi Street, Heilongjiang, Harbin 150001 (China); Ke, H.; Rao, J.C.; Zhou, Y. [Institute for Advanced Ceramics, Department of Materials Science and Engineering, Harbin Institute of Technology, No. 92, West Da-Zhi Street, Heilongjiang, Harbin 150001 (China)

    2010-04-09

    Ferroelectric PMN-PT (68/32) thin films, about 250 nm in thickness, have been successfully grown on Pt/Ti/SiO{sub 2}/Si substrate by a modified sol-gel process. Pure perovskite phase with highly (1 1 1)-preferred orientation, determined by X-ray diffraction, was formed in the PMN-PT thin films when annealed at 650 {sup o}C. The pyrochlore phase has been effectively avoided through a variation of the processing parameters such as Mg content, Mg precursor and annealing temperature during thin film deposition. FE-SEM investigation showed that the films have a smooth and crack-free surface with densely packed grains after annealed at 650 {sup o}C. The annealed films exhibited well-defined hysteresis loops, with a respective remanent polarization P{sub r} of 16.1 {mu}C/cm{sup 2} and coercive field E{sub c} of 71.2 kV/cm at an applied electric field of 400 kV/cm at room temperature.

  6. Capability Study of Ti, Cr, W, Ta and Pt as Seed Layers for Electrodeposited Platinum Films on γ-Al2O3 for High Temperature and Harsh Environment Applications

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2017-01-01

    Full Text Available High temperature surface acoustic wave sensors based on radio frequency identification technology require adequate antennas of high efficiency and thermal stability for the signal transmission. Platinum is well known and frequently used as a material of choice for high temperature and harsh environment applications because of the high melting point and its chemical stability. Therefore, one way to realize high temperature stable antennas is the combination of a Pt metallization on an Al 2 O 3 substrate. As a cost-effective technique, the Pt film is deposited via electrochemical deposition. For this growth procedure, a pre-deposited metallization on the Al 2 O 3 layer is required. This paper analyzes the influence of various seed layers (Ta, Ti, W, Cr, Pt on the morphology, stability and electrical properties of the electrochemically-grown Pt thick film after heat treatments up to 1000 ∘ C in air. We find an oxidation of all adhesion layers except for Pt, for which the best electrical properties were measured. Although significant areas of the films delaminate from the substrate, individual anchor structures retain a stable connection between the Pt layer and the rough Al 2 O 3 substrate.

  7. Experimental study of heat-treated thin film Ti/Pt heater and temperature sensor properties on a Si microfluidic platform

    Science.gov (United States)

    Resnik, D.; Vrtačnik, D.; Možek, M.; Pečar, B.; Amon, S.

    2011-02-01

    Design, fabrication and characterization of thin film Ti/Pt heaters and integrated temperature sensors on a Si microfluidic platform are presented. Ti/Pt heaters and sensors provide controlled heating of microchannels realized on the opposite side of the Si platform. Ti/Pt heaters and sensors were fabricated simultaneously by a dc sputtering method and a lift-off process. Thermal annealing of deposited Ti/Pt layers in the temperature range of 300-700 °C was investigated revealing a strong impact on the Ti/Pt resistivity and, consequently, on the final resistance of fabricated heaters and sensors. Furthermore, it was determined that the temperature coefficient of resistance (TCR) for Ti/Pt temperature sensors and the heater increased with the annealing temperature. Microstructural analysis of deposited and annealed Ti/Pt layers carried out by AES and AFM revealed that recrystallization followed by a grain growth process of heat-treated Ti/Pt layers started at around 500 °C and correlated well with the behavior of electrical properties, but not with the TCR behavior of annealed layers. To reduce the heat losses of the heated Si platform, the heater and temperature sensors were covered hermetically by anodically bonded Pyrex glass with a prefabricated insulating cavity. According to this approach the power consumption was reduced by more than 25% due to the improved thermal insulation. Additional insulation steps implemented during thermal characterization of the assembled microfluidic platform further reduced the power consumption, but also increased the time response of the microfluidic reactor.

  8. Magnetic properties and inhomogeneous phase transition in (Fe sub x Co sub 0 sub . sub 5 sub - sub x)Pt sub 0 sub . sub 5 films

    CERN Document Server

    Jang, P W; Na, J G; Lee, S R

    1999-01-01

    (Fe sub x Co sub 0 sub . sub 5 sub - sub x)Pt sub 0 sub . sub 5 ternary thin films were deposited on glass substrates by using a dc sputtering method at room temperature and were subsequently annealed at 700 .deg. C in a high vacuum. A high degree of the (111) preferred orientation could be obtained in all the as-deposited films and was not destroyed, even though post annealing. The CoPt and the FePt binary alloys were completely mixed and had a L1 sub o -type ordered structure, as confirmed by single (222) peaks and by the linear variation of the lattice constant a sub o. The ordered structure of the FePt alloy was thought to have formed from the disordered structure by an inhomogeneous process, which was confirmed by the asymmetric peak shapes. The lattice parameter a sub o varied linearly with the Fe content while the coercivity showed a minimum value at the equiatomic composition of the Fe and the Co atoms.

  9. Chemical solution deposition of functional oxide thin films

    CERN Document Server

    Schneller, Theodor; Kosec, Marija

    2014-01-01

    Chemical Solution Deposition (CSD) is a highly-flexible and inexpensive technique for the fabrication of functional oxide thin films. Featuring nearly 400 illustrations, this text covers all aspects of the technique.

  10. Dual Ion Beam Deposition Of Diamond Films On Optical Elements

    Science.gov (United States)

    Deutchman, Arnold H.; Partyka, Robert J.; Lewis, J. C.

    1990-01-01

    Diamond film deposition processes are of great interest because of their potential use for the formation of both protective as well as anti-reflective coatings on the surfaces of optical elements. Conventional plasma-assisted chemical vapor deposition diamond coating processes are not ideal for use on optical components because of the high processing temperatures required, and difficulties faced in nucleating films on most optical substrate materials. A unique dual ion beam deposition technique has been developed which now makes possible deposition of diamond films on a wide variety of optical elements. The new DIOND process operates at temperatures below 150 aegrees Farenheit, and has been used to nucleate and grow both diamondlike carbon and diamond films on a wide variety of optical :taterials including borosilicate glass, quartz glass, plastic, ZnS, ZnSe, Si, and Ge.

  11. Chemical bath ZnSe thin films: deposition and characterisation

    Science.gov (United States)

    Lokhande, C. D.; Patil, P. S.; Ennaoui, A.; Tributsch, H.

    1998-01-01

    The zinc selenide (ZnSe) thin films have been deposited by a simple and inexpensive chemical bath deposition (CBD) method. The selenourea was used as a selenide ion source. The ZnSe films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDAX), Rutherford back scattering (RBS), and optical absorption. The as-deposited ZnSe films on various substrates are found to be amorphous and contain O2 and N2 in addition to Zn and Se. The optical band gap of the film is estimated to be 2.9 eV. The films are photoactive as evidenced by time resolved microwave conductivity (TRMC).

  12. Nonepitaxial growth of a (001) textured L10 Fe-Pt film in H2 and N2 annealing atmospheres

    Institute of Scientific and Technical Information of China (English)

    WU Peiwen; HU Xuerang; QIAN Jun; YUAN Jun

    2006-01-01

    A nonepitaxial (001) textured Fe-Pt alloyed film was obtained by annealing Fe/Pt multilayers in H2. No such nonepitaxial (001) texture was observed for similar multilayers annealed in N2 atmosphere. Sensitive electron energy loss spectroscopy and the left shift of the L10 FePt (111) diffraction peak indicate oxidation in the N2 annealed samples. The oxidation dramatically degrades the (001) texture of the Fe-Pt film and induces the composition change in the alloyed layer.The relation between the texture formation and oxidation was discussed.

  13. Factors controlling the microstructure of Ce0.9Gd0.1O2-δ films in pulsed laser deposition process

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, S.; Döbeli, M.;

    2010-01-01

    Films of Ce0.9Gd0.1O2-delta (CGO10) are prepared at a range of conditions by pulsed laser deposition (PLD) on a single crystal Si (100) and MgO (100), and on a polycrystalline Pt/MgO (100) substrate. The relationship between the film microstructure, crystallography, chemical composition and PLD...... processing parameters is studied. It is found that the laser fluence has no significant impact on the film density, whereas the substrate temperature and the oxygen pressure are of essential importance for the film microstructure development. The reduction of deposition temperature, down to 250 oC, together...

  14. FePt Thin Films: Fundamentals and Applications

    NARCIS (Netherlands)

    Lodder, J.C.; Nguyen, L.T.

    2005-01-01

    Recently, high magnetic anisotropy materials have received much attention to meet the demands of applications in the field of information technologies (Magnetic Films: Anisotropy). For example, in magnetic recording, as the bit size is reduced to nano dimension, material with high Ku value is needed

  15. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stöber, Laura, E-mail: laura.stoeber@tuwien.ac.at; Patocka, Florian, E-mail: florian.patocka@tuwien.ac.at; Schneider, Michael, E-mail: michael.schneider@tuwien.ac.at; Schmid, Ulrich, E-mail: ulrich.e366.schmid@tuwien.ac.at [Institute of Sensor and Actuator Systems, TU Wien, Gußhausstraße 27-29, A-1040 Vienna (Austria); Konrath, Jens Peter, E-mail: jenspeter.konrath@infineon.com; Haberl, Verena, E-mail: verena.haberl@infineon.com [Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)

    2016-03-15

    In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo{sub 2}N) thin films. Various argon and nitrogen gas compositions are applied for thin film synthetization, and the amount of nitrogen incorporation is determined by Auger measurements. Furthermore, effusion measurements identifying the binding conditions of the nitrogen in the thin film are performed up to 1000 °C. These results are in excellent agreement with film stress and scanning electron microscope analyses, both indicating stable film properties up to annealing temperatures of 500 °C.

  16. Continuous wave infrared laser deposition of organic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yaginuma, Seiichiro [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Yamaguchi, Jun [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Haemori, Masamitsu [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Itaka, Kenji [Department of Advanced Materials Science, Graduate School of Frontier Sciences, Univesity of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan); Matsumoto, Yuji [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Kondo, Michio [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Koinuma, Hideomi [Department of Advanced Materials Science, Graduate School of Frontier Sciences, Univesity of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan)

    2007-04-15

    We developed a continuous-wave infrared laser molecular beam epitaxy (CW-IR-LMBE) optimized for the fabrication of organic semiconductor films. The crystal quality of these organic thin films deposited by CW-IR-LMBE was substantially the same as those deposited by thermal evaporation. Due to the possibility of quick switching of evaporation sources, CW-IR-LMBE is especially advantageous for rapid screening of composition, thickness, and fabrication parameters in materials and device optimization based on combinatorial technology.

  17. ZnS thin film deposited with chemical bath deposition process directed by different stirring speeds

    Science.gov (United States)

    Zhang, Y.; Dang, X. Y.; Jin, J.; Yu, T.; Li, B. Z.; He, Q.; Li, F. Y.; Sun, Y.

    2010-09-01

    In this combined film thickness, scanning electron microscopy (SEM), X-ray diffraction and optical properties study, we explore the effects of different stirring speeds on the growth and optical properties of ZnS film deposited by CBD method. From the disclosed changes of thickness of ZnS film, we conclude that film thickness is independent of the stirring speeds in the heterogeneous process (deposition time less than 40 min), but increases with the stirring speeds and/or deposition time increasing in the homogeneous process. Grazing incident X-ray diffraction (GIXRD) and the study of optical properties disclosed that the ZnS films grown with different stirring speeds show partially crystallized film and exhibit good transmittance (70-88% in the visible region), but the stirring speeds cannot give much effects on the structure and optical properties in the homogeneous process.

  18. Hardness and stress of amorphous carbon film deposited by glow discharge and ion beam assisting deposition

    CERN Document Server

    Marques, F C

    2000-01-01

    The hardness and stress of amorphous carbon films prepared by glow discharge and by ion beam assisting deposition are investigated. Relatively hard and almost stress free amorphous carbon films were deposited by the glow discharge technique. On the other hand, by using the ion beam assisting deposition, hard films were also obtained with a stress of the same order of those found in tetrahedral amorphous carbon films. A structural analysis indicates that all films are composed of a sp sup 2 -rich network. These results contradict the currently accepted concept that both stress and hardness are only related to the concentration of sp sup 3 sites. Furthermore, the same results also indicate that the sp sup 2 sites may also contribute to the hardness of the films.

  19. Atomically flat surface of (0 0 1) textured FePt thin films by residual stress control

    Science.gov (United States)

    Liu, S. H.; Hsiao, S. N.; Chou, C. L.; Chen, S. K.; Lee, H. Y.

    2015-11-01

    Single-layered Fe52Pt48 films with thickness of 10 nm were sputter-deposited on glass substrates. Rapid thermal annealing with different heating rates (10-110 K/s) was applied to transform as-deposited fcc phase into L10 phase and meanwhile to align [0 0 1]-axis of L10 crystal along plane normal direction. Based on X-ray diffractometry using synchrotron radiation source, the texture coefficient of (0 0 1)-plane increases with increasing heating rate from 10 to 40 K/s, which is correlated with perpendicular magnetic anisotropy and in-plane tensile stress analyzed by asymmetric sin2 ψ method. Furthermore, it was revealed by atomic force microscopy that the dewetting process occurred as heating rate was raised up to 80 K/s and higher. The change in the microstructure due to stress relaxation leads to the degradation of (0 0 1) orientation and magnetic properties. Surface roughness is closely related to the in-plane tensile stress. Enhanced perpendicular magnetic anisotropy and atomically flat surface were achieved for the samples annealed at 40 K/s, which may be suitable for further practical applications. This work also suggests a feasible way for surface engineering by controlling internal stress of the FePt without introducing cap layer.

  20. Thin film zinc oxide deposited by CVD and PVD

    Science.gov (United States)

    Hamelmann, Frank U.

    2016-10-01

    Zinc oxide is known as a mineral since 1810, but it came to scientific interest after its optoelectronic properties found to be tuneable by p-type doping. Since the late 1980’s the number of publications increased exponentially. All thin film deposition technologies, including sol-gel and spray pyrolysis, are able to produce ZnO films. However, for outstanding properties and specific doping, only chemical vapor deposition and physical vapor deposition have shown so far satisfying results in terms of high conductivity and high transparency. In this paper the different possibilities for doping will be discussed, some important applications of doped ZnO thin films will be presented. The deposition technologies used for industrial applications are shown in this paper. Especially sputtering of aluminium doped Zinc Oxide (ZnO:Al or AZO) and LPCVD of boron doped Zinc Oxide (ZnO:B or BZO) are used for the commercial production of transparent conductive oxide films on glass used for thin film photovoltaic cells. For this special application the typical process development for large area deposition is presented, with the important trade-off between optical properties (transparency and ability for light scattering) and electrical properties (conductivity). Also, the long term stability of doped ZnO films is important for applications, humidity in the ambient is often the reason for degradation of the films. The differences between the mentioned materials are presented.

  1. Contamination control in ion beam sputter-deposited films

    Science.gov (United States)

    Pearson, David I. C.; Pochon, Sebastien; Cooke, Mike

    2013-09-01

    The conventional wisdom to guarantee high purity thin films in IBSD has been to use a large vacuum chamber usually in excess of 1 m3. The chamber size was important to minimise the effect of reflected high energy particles from the target surface sputtering chamber materials onto the substrate and to allow the use of large targets to avoid beam overspill onto chamber furniture. An improved understanding of beam trajectories and re-sputtered material paths has allowed the deposition of thin films with very low metallic impurity content in a chamber volume below 0.5 m3. Thus, by optimizing the sputter ion source, target and substrate configuration, and by arranging suitable shielding made of an appropriate material in the process chamber, the levels of contaminants in the deposited films have been reduced to a minimum. With this optimum hardware arrangement, the ion beam process parameters were then optimized with respect to the ppm levels of contaminants measured in the films by SIMS analysis. Using the deposition of SiO2 as a standard material for DSIMS composition analysis and impurity level determination, it has been shown that our IBS deposition tool is capable of depositing films with contamination levels of <50ppm for the total of all metal impurities in the deposited films.

  2. Characterization of polymer thin films obtained by pulsed laser deposition

    Science.gov (United States)

    Palla-Papavlu, A.; Dinca, V.; Ion, V.; Moldovan, A.; Mitu, B.; Luculescu, C.; Dinescu, M.

    2011-04-01

    The development of laser techniques for the deposition of polymer and biomaterial thin films on solid surfaces in a controlled manner has attracted great attention during the last few years. Here we report the deposition of thin polymer films, namely Polyepichlorhydrin by pulsed laser deposition. Polyepichlorhydrin polymer was deposited on flat substrate (i.e. silicon) using an NdYAG laser (266 nm, 5 ns pulse duration and 10 Hz repetition rate). The obtained thin films have been characterized by atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and spectroscopic ellipsometry. It was found that for laser fluences up to 1.5 J/cm 2 the chemical structure of the deposited polyepichlorhydrin polymer thin layers resembles to the native polymer, whilst by increasing the laser fluence above 1.5 J/cm 2 the polyepichlorohydrin films present deviations from the bulk polymer. Morphological investigations (atomic force microscopy and scanning electron microscopy) reveal continuous polyepichlorhydrin thin films for a relatively narrow range of fluences (1-1.5 J/cm 2). The wavelength dependence of the refractive index and extinction coefficient was determined by ellipsometry studies which lead to new insights about the material. The obtained results indicate that pulsed laser deposition method is potentially useful for the fabrication of polymer thin films to be used in applications including electronics, microsensor or bioengineering industries.

  3. Thickness dependence of spin torque ferromagnetic resonance in Co{sub 75}Fe{sub 25}/Pt bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Ganguly, A.; Barman, A., E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sec III, Salt Lake, Kolkata 700 098 (India); Kondou, K., E-mail: kkondou@riken.jp [RIKEN-CEMS, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sukegawa, H.; Mitani, S. [National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan); Kasai, S. [RIKEN-CEMS, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan); Niimi, Y. [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan); Otani, Y. [RIKEN-CEMS, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan)

    2014-02-17

    The spin Hall angle of Pt in Co{sub 75}Fe{sub 25}/Pt bilayer films was experimentally investigated by means of the spin-torque ferromagnetic resonance and the modulation of damping measurements. By comparing the present results with the Ni{sub 80}Fe{sub 20}/Pt system, we found that the ferromagnetic layer underneath the Pt one greatly affects the estimation of the spin Hall angle. We also discuss the spin diffusion length of Pt and the ferromagnetic thickness dependence of the Gilbert damping coefficient.

  4. Stress development during deposition of CNx thin films

    Science.gov (United States)

    Broitman, E.; Zheng, W. T.; Sjöström, H.; Ivanov, I.; Greene, J. E.; Sundgren, J.-E.

    1998-05-01

    We have investigated the influence of deposition parameters on stress generation in CNx (0.3films deposited onto Si(001) substrates by reactive magnetron sputtering of C in pure N2 discharges. Film stress, σ, which in all cases is compressive, decreases with an increase in the N2 pressure, PN2, due to structural changes induced by the pressure-dependent variation in the average energy of particles bombarding the film during deposition. The film stress σ is also a function of the film growth temperature, Ts, and exhibits a maximum value of ˜5 GPa at 350 °C. Under these conditions, the films have a distorted microstructure consisting of a three-dimensional, primarily sp2 bonded, network. In contrast, films deposited at Ts<200 °C with a low stress are amorphous. At 350 °Cfilms grown at 350 °C exhibit the highest hardness and elasticity.

  5. Lanthanum titanium perovskite compound: Thin film deposition and high frequency dielectric characterization

    Energy Technology Data Exchange (ETDEWEB)

    Le Paven, C., E-mail: claire.lepaven@univ-rennes1.fr [Institut d' Electronique et de Télécommunications de Rennes (IETR, UMR-CNRS 6164), Equipe Matériaux Fonctionnels, IUT Saint Brieuc, Université de Rennes 1, 22000 Saint Brieuc (France); Lu, Y. [Institut d' Electronique et de Télécommunications de Rennes (IETR, UMR-CNRS 6164), Equipe Matériaux Fonctionnels, IUT Saint Brieuc, Université de Rennes 1, 22000 Saint Brieuc (France); Nguyen, H.V. [Institut d' Electronique et de Télécommunications de Rennes (IETR, UMR-CNRS 6164), Equipe Matériaux Fonctionnels, IUT Saint Brieuc, Université de Rennes 1, 22000 Saint Brieuc (France); CEA LETI, Minatec Campus, 38054 Grenoble (France); Benzerga, R.; Le Gendre, L. [Institut d' Electronique et de Télécommunications de Rennes (IETR, UMR-CNRS 6164), Equipe Matériaux Fonctionnels, IUT Saint Brieuc, Université de Rennes 1, 22000 Saint Brieuc (France); Rioual, S. [Laboratoire de Magnétisme de Brest (EA CNRS 4522), Université de Bretagne Occidentale, 29000 Brest (France); Benzegoutta, D. [Institut des Nanosciences de Paris (INSP, UMR CNRS 7588), Université Pierre et Marie Curie, 75005 Paris (France); Tessier, F.; Cheviré, F. [Institut des Sciences Chimiques de Rennes (ISCR, UMR-CNRS 6226), Equipe Verres et Céramiques, Université de Rennes 1, 35000 Rennes (France); and others

    2014-02-28

    Perovskite lanthanum titanium oxide thin films were deposited on (001) MgO, (001) LaAlO{sub 3} and Pt(111)/TiO{sub 2}/SiO{sub 2}/(001)Si substrates by RF magnetron sputtering, using a La{sub 2}Ti{sub 2}O{sub 7} homemade target sputtered under oxygen reactive plasma. The films deposited at 800 °C display a crystalline growth different than those reported on monoclinic ferroelectric La{sub 2}Ti{sub 2}O{sub 7} films. X-ray photoelectron spectroscopy analysis shows the presence of titanium as Ti{sup 4+} ions, with no trace of Ti{sup 3+}, and provides a La/Ti ratio of 1.02. The depositions being performed from a La{sub 2}Ti{sub 2}O{sub 7} target under oxygen rich plasma, the same composition (La{sub 2}Ti{sub 2}O{sub 7}) is proposed for the deposited films, with an unusual orthorhombic cell and Cmc2{sub 1} space group. The films have a textured growth on MgO and Pt/Si substrates, and are epitaxially grown on LaAlO{sub 3} substrate. The dielectric characterization displays stable values of the dielectric constant and of the losses in the frequency range [0.1–20] GHz. No variation of the dielectric constant has been observed when a DC electric field up to 250 kV/cm was applied, which does not match a classical ferroelectric behavior at high frequencies and room temperature for the proposed La{sub 2}Ti{sub 2}O{sub 7} orthorhombic phase. At 10 GHz and room temperature, the dielectric constant of the obtained La{sub 2}Ti{sub 2}O{sub 7} films is ε ∼ 60 and the losses are low (tanδ < 0.02). - Highlights: • Lanthanum titanium oxide films were deposited by reactive magnetron sputtering. • A La{sub 2}Ti{sub 2}O{sub 7} chemical composition is proposed, with an unusual orthorhombic cell. • At 10 GHz, the dielectric losses are lower than 0.02. • No variation of the dielectric constant is observed under DC electric biasing.

  6. Pulsed laser deposition and characterisation of thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Morone, A. [CNR, zona industriale di Tito Scalo, Potenza (Italy). Istituto per i Materiali Speciali

    1996-09-01

    Same concepts on pulsed laser deposition of thin films will be discussed and same examples of high transition temperature (HTc) BiSrCaCuO (BISCO) and low transition temperature NbN/MgO/NbN multilayers will be presented. X-ray and others characterizations of these films will be reported and discussed. Electrical properties of superconducting thin films will be realized as a function of structural and morphological aspect.

  7. Characterization of CdTe films deposited at various bath temperatures and concentrations using electrophoretic deposition.

    Science.gov (United States)

    Daud, Mohd Norizam Md; Zakaria, Azmi; Jafari, Atefeh; Ghazali, Mohd Sabri Mohd; Abdullah, Wan Rafizah Wan; Zainal, Zulkarnain

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  8. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    Zulkarnain Zainal

    2012-05-01

    Full Text Available CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111 orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  9. Electrical conductivity and crystallization of amorphous bismuth ruthenate thin films deposited by spray pyrolysis.

    Science.gov (United States)

    Ryll, Thomas; Brunner, Andreas; Ellenbroek, Stefan; Bieberle-Hutter, Anja; Rupp, Jennifer L M; Gauckler, Ludwig J

    2010-11-14

    Amorphous oxide thin films with tailored functionality will be crucial for the next generation of micro-electro-mechanical-systems (MEMS). Due to potentially favorable electronic and catalytic properties, amorphous bismuth ruthenate thin films might be applied in this regard. We report on the deposition of amorphous bismuth ruthenate thin films by spray pyrolysis, their crystallization behavior and electrical conductivity. At room temperature the 200 nm thin amorphous films exhibit a high electrical conductivity of 7.7 × 10(4) S m(-1), which was found to be slightly thermally activated (E(a) = 4.1 × 10(-3) eV). It follows that a long-range order of the RuO(6) octahedra is no precondition for the electrical conductivity of Bi(3)Ru(3)O(11). Upon heating to the temperature range between 490 °C and 580 °C the initially amorphous films crystallize rapidly. Simultaneously, a transition from a dense and continuous film to isolated Bi(3)Ru(3)O(11) particles on the substrate takes place. Solid-state agglomeration is proposed as the mechanism responsible for disintegration. The area specific resistance of Bi(3)Ru(3)O(11) particles contacted by Pt paste on gadolinia doped ceria electrolyte pellets was found to be 7 Ω cm(2) at 607 °C in air. Amorphous bismuth ruthenate thin films are proposed for application in electrochemical devices operating at low temperatures, where a high electrical conductivity is required.

  10. 80-MHz intravascular ultrasound transducer using PMN-PT free-standing film.

    Science.gov (United States)

    Li, Xiang; Wu, Wei; Chung, Youngsoo; Shih, Wan Y; Shih, Wei-Heng; Zhou, Qifa; Shung, K Kirk

    2011-11-01

    [Pb(Mg(1/3)Nb(2/3))O(3)](0.63)[PbTiO(3)](0.37) (PMN-PT) free-standing film of comparable piezoelectric properties to bulk material with thickness of 30 μm has been fabricated using a modified precursor coating approach. At 1 kHz, the dielectric permittivity and loss were 4364 and 0.033, respectively. The remnant polarization and coercive field were 28 μC/cm(2) and 18.43 kV/cm. The electromechanical coupling coefficient k(t) was measured to be 0.55, which was close to that of bulk PMN-PT single-crystal material. Based on this film, high-frequency (82 MHz) miniature ultrasonic transducers were fabricated with 65% bandwidth and 23 dB insertion loss. Axial and lateral resolutions were determined to be as high as 35 and 176 μm. In vitro intravascular imaging on healthy rabbit aorta was performed using the thin film transducers. In comparison with a 35-MHz IVUS transducer, the 80-MHz transducer showed superior resolution and contrast with satisfactory penetration depth. The imaging results suggest that PMN-PT free-standing thin film technology is a feasible and efficient way to fabricate very-high-frequency ultrasonic transducers.

  11. Valence-EELS analysis of local electronic and optical properties of PMN-PT epitaxial film

    Energy Technology Data Exchange (ETDEWEB)

    Kiguchi, Takanori [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)], E-mail: tkiguchi@imr.tohoku.ac.jp; Wakiya, Naoki [Department of Materials Science, Shizuoka University, 3-5-1 Johoku, Hamamatsu, Shizuoka 432-8561 (Japan); Shinozaki, Kazuo [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Konno, Toyohiko J. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2009-04-15

    This study investigated local electrical and optical properties of Pb(Mg{sub 0.39}Nb{sub 0.61})-0.34 mol%PbTiO{sub 3} solid solution (PMN-PT) film stacked on Si (0 0 1) wafer with (La,Sr)CoO{sub 3-x}/CeO{sub 2}/YSZ buffer layers. TEM-VEELS analysis of the PMN-PT thin film, which was grown epitaxially on the Si substrate with two coexisting phases of pseudocubic and tetragonal morphology, was firstly conducted using the TEM-VEELS method. The ELF has shown a bulk plasmon peak and two interband plasmon peaks. The interband transition has been interpreted in comparison with the joint density of state obtained from the measured dielectric function and the density of state calculated by the density functional theory. The interband transition from the O 2p band to Nb 4d/Ti 3d bands determines the optical properties around the band gap. The optical absorption of PMN-PT film has shown the band gap of 3.5 {+-} 0.2 V. The refractive index derived from the TEM-VEELS analysis in the nano-region of the film has agreed with that obtained with the conventional optical measurement from the macroscopic region.

  12. Perpendicular magnetic anisotropy of non-epitaxial hexagonal Co{sub 50}Pt{sub 50} thin films prepared at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, F.T., E-mail: ftyuan@gmail.com [iSentek Ltd., Advanced Sensor Laboratory, New Taipei City 22101, Taiwan (China); Chang, H.W., E-mail: wei0208@gmail.com [Department of Applied Physics, Tunghai University, Taichung 40704, Taiwan (China); Lee, P.Y.; Chang, C.Y. [Department of Applied Physics, Tunghai University, Taichung 40704, Taiwan (China); Chi, C.C. [Department of Materials Sciences and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Ouyang, H., E-mail: houyang@mx.nthu.edu.tw [Department of Materials Sciences and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2015-04-15

    Highlights: • In this paper, we propose a non-epitaxially grown PMA thin film of disorder hexagonal Co{sub 50}Pt{sub 50} which can satisfy all the requirements at once. • Although the preparation temperature is at room temperature and no post annealing is required, the film also shows good thermal stability up to 400 °C. • Moreover, the easy-controlling single layer deposition process of the film largely enhances the feasibility of practical production. • Significant PMA is achieved in a wide range of film thickness from 2 nm to 20 nm, which expands the usage form a GMR or TMR magnetic junctions to perpendicular spin polarizer for spin current related engineering. • The presented results may open new opportunities for advanced spintronic devices. - Abstract: Non-epitaxially induced perpendicular magnetic anisotropy (PMA) of Co{sub 50}Pt{sub 50} thin films at room temperature (RT) is reported. The CoPt film having a disordered hcp structure shows a magnetocrystalline anisotropy (K{sub u}{sup RT}) of 1–2 × 10{sup 6} erg/cm{sup 3} in a wide range of layer thickness from 2 to 20 nm. K{sub u}{sup RT} of about 1 × 10{sup 6} erg/cm{sup 3} can be preserved after a 400 °C-thermal cycle in the 5-nm-thick sample. Moderate PMA, large thickness range, simple preparation process, low formation temperature but good thermal stability make presented hcp CoPt become a remarkable option for advanced spintronic devices.

  13. Electrochemical atomic layer deposition of Pt nanostructures on fuel cell gas diffusion layer

    CSIR Research Space (South Africa)

    Modibedi, M

    2010-12-01

    Full Text Available . Acta 42(10) 1587. 4. Stickney, J.L., et al., (2002) Encyclopedia of Electrochemistry, Wiley-VCH: Weinheim 513 5. Mkwizu T.S., Mathe M.K., Cukrowski I., (2010) Langmuir 26 (1) 570. Electrochemical Atomic Layer Deposition of Pt nanostructures on fuel... cell gas diffusion layer Mmalewane Modibedi1, Tumaini Mkwizu1, 2, Nikiwe Kunjuzwa1,3 , Kenneth Ozoemena1 and Mkhulu Mathe1 1. Energy and Processes, Materials Science and Manufacturing, The Council for Scientific and Industrial Research (CSIR...

  14. Atomic Layer Deposition of Pt Nanoparticles for Microengine with Promoted Catalytic Motion.

    Science.gov (United States)

    Jiang, Chi; Huang, Gaoshan; Ding, Shi-Jin; Dong, Hongliang; Men, Chuanling; Mei, Yongfeng

    2016-12-01

    Nanoparticle-decorated tubular microengines were synthesized by a combination of rolled-up nanotechnology and atomic layer deposition. The presence of Pt nanoparticles with different sizes and distributions on the walls of microengines fabricated from bilayer nanomembranes with different materials results in promoted catalytic reaction efficiency, which leads to an ultrafast speed (the highest speed 3200 μm/s). The motion speed of the decorated microengines fits the theoretical model very well, suggesting that the larger surface area is mainly responsible for the acceleration of the motion speed. The high-speed nanoparticle-decorated microengines hold considerable promise for a variety of applications.

  15. Luminescent thin films by the chemical aerosol deposition technology (CADT)

    NARCIS (Netherlands)

    Martin, F.J.; Martin, F.J.; Albers, H.; Lambeck, Paul; Popma, T.J.A.; van de Velde, G.M.H.

    1992-01-01

    Zinc sulphide thin films have been deposited with CART using zinc chlorideand zinc acetylacetonate as Zn compounds and thiourea and 1,1,3,3-tetramethylthiourea as S compounds soluted in methanol, ethanol, isopropanol and cellosolve. After optimalization of the deposition process homogeneous layers

  16. Ubiquitous pentacene monolayer on metals deposited onto pentacene films.

    Science.gov (United States)

    Jaeckel, B; Sambur, J B; Parkinson, B A

    2007-11-01

    Photoelectron spectroscopy (XPS and UPS) was used to study the deposition of metal layers (Ag, Cu, and Au) onto pentacene films. Very low work functions were measured (PhiAg = 3.91 eV, PhiCu = 3.93 eV, and PhiAu = 4.3 eV) for all of the metals, in agreement with results from the literature. The intensities of the C 1s core-level signals from pentacene that were monitored during stepwise metal deposition leveled off at a value of about 30% of a thick pentacene film. This C 1s intensity is comparable to that of one monolayer of pentacene deposited onto the respective metal. The valence band spectra of metals deposited onto pentacene and spectra collected for pentacene deposited onto bare metal surfaces are very similar. These findings lead to the conclusion that approximately one monolayer of pentacene is always present on top of the freshly deposited metal film, which explains the very low work function of the metals when they are deposited onto organic films. We expect similar behavior with other nonreactive metals deposited onto stable organic layers.

  17. Stoichiometry controlled oxide thin film growth by pulsed laser deposition

    NARCIS (Netherlands)

    Groenen, Rik; Smit, Jasper; Orsel, Kasper; Vailionis, Arturas; Bastiaens, Bert; Huijben, Mark; Boller, Klaus; Rijnders, Guus; Koster, Gertjan

    2015-01-01

    The oxidation of species in the plasma plume during pulsed laser deposition controls both the stoichiometry as well as the growth kinetics of the deposited SrTiO3 thin films, instead of the commonly assumed mass distribution in the plasma plume and the kinetic energy of the arriving species. It was

  18. Highly conformal and high-ionic conductivity thin-film electrolyte for 3D-structured micro batteries: Characterization of LiPON film deposited by MOCVD method

    Science.gov (United States)

    Fujibayashi, Takashi; Kubota, Yusuke; Iwabuchi, Katsuhiko; Yoshii, Naoki

    2017-08-01

    This paper reports a lithium phosphorus oxynitride (LiPON) thin-film electrolyte deposited using a metalorganic-chemical vapor deposition (MOCVD) method for 3D-structured micro batteries. It is shown that the MOCVD-LiPON film has both highly-conformal step coverage on a patterned substrate with line/space=2μm/2μm and aspect ratio=1 (51±3 nm) and high-ionic conductivity for very thin films deposited at 4.7 nm/min (5.9×10-6 S/cm for 190 nm and 5.3×10-6 S/cm for 95 nm). Detailed material characterization attributes the enhancement in ionic conductivity to a decrease in nanocrystallite size and improvement in chemical-composition uniformity in the film. In addition, electrochemical characterization of an all-solid-state thin-film battery fabricated with the 190 nm-thick LiPON film (Si substrate/Ti/Pt/LiCoO2/LiPON/a-Si:H/Cu) demonstrates that the LiPON film can successfully act as the electrolyte for lithium-ion batteries. Therefore, the MOCVD-LiPON film is a promising candidate material to realize 3D-structured micro batteries in the near future.

  19. Highly conformal and high-ionic conductivity thin-film electrolyte for 3D-structured micro batteries: Characterization of LiPON film deposited by MOCVD method

    Directory of Open Access Journals (Sweden)

    Takashi Fujibayashi

    2017-08-01

    Full Text Available This paper reports a lithium phosphorus oxynitride (LiPON thin-film electrolyte deposited using a metalorganic-chemical vapor deposition (MOCVD method for 3D-structured micro batteries. It is shown that the MOCVD-LiPON film has both highly-conformal step coverage on a patterned substrate with line/space=2μm/2μm and aspect ratio=1 (51±3 nm and high-ionic conductivity for very thin films deposited at 4.7 nm/min (5.9×10-6 S/cm for 190 nm and 5.3×10-6 S/cm for 95 nm. Detailed material characterization attributes the enhancement in ionic conductivity to a decrease in nanocrystallite size and improvement in chemical-composition uniformity in the film. In addition, electrochemical characterization of an all-solid-state thin-film battery fabricated with the 190 nm-thick LiPON film (Si substrate/Ti/Pt/LiCoO2/LiPON/a-Si:H/Cu demonstrates that the LiPON film can successfully act as the electrolyte for lithium-ion batteries. Therefore, the MOCVD-LiPON film is a promising candidate material to realize 3D-structured micro batteries in the near future.

  20. Vacuum deposition of stoichiometric crystalline PbS films: The effect of sulfurizing environment during deposition

    Science.gov (United States)

    Singh, B. P.; Kumar, R.; Kumar, A.; Tyagi, R. C.

    2015-10-01

    Thin film of lead sulfide (PbS) was deposited onto highly cleaned glass and quartz substrates using a vacuum thermal evaporation technique. The effect of the sulfurizing environment on the growth and properties of vacuum-deposited PbS thin film was studied. The ambient sulfurizing environment was created by thermal decomposition of thiourea inside the vacuum chamber during deposition to maintain the stoichiometry and quality of the PbS film. The sulfurizing gas H2S, produced in the thermal decomposition of the solid sulfur containing thiourea readily combines with the cations (Pb2+) without leaving any anions (S2-) at the substrates and also has not produced any excess of sulfur at the substrates. The deposited film was characterized by optical spectroscopy, x-ray diffraction patterns, scanning electron micrographs with energy dispersive analysis of x-rays, and atomic force micrographs. The physical characterization of the deposited PbS film revealed that the surface of film grown in the sulfurizing environment improved and contained more stoichiometric sulfur in comparison to film deposited without the sulfurizing environment.

  1. Thin-film organic photonics molecular layer deposition and applications

    CERN Document Server

    Yoshimura, Tetsuzo

    2011-01-01

    Among the many atomic/molecular assembling techniques used to develop artificial materials, molecular layer deposition (MLD) continues to receive special attention as the next-generation growth technique for organic thin-film materials used in photonics and electronics. Thin-Film Organic Photonics: Molecular Layer Deposition and Applications describes how photonic/electronic properties of thin films can be improved through MLD, which enables precise control of atomic and molecular arrangements to construct a wire network that achieves ""three-dimensional growth"". MLD facilitates dot-by-dot--o

  2. Atomic Layer Deposition of Pt Nanoparticles within the Cages of MIL-101: A Mild and Recyclable Hydrogenation Catalyst

    Directory of Open Access Journals (Sweden)

    Karen Leus

    2016-03-01

    Full Text Available We present the in situ synthesis of Pt nanoparticles within MIL-101-Cr (MIL = Materials Institute Lavoisier by means of atomic layer deposition (ALD. The obtained Pt@MIL-101 materials were characterized by means of N2 adsorption and X-ray powder diffraction (XRPD measurements, showing that the structure of the metal organic framework was well preserved during the ALD deposition. X-ray fluorescence (XRF and transmission electron microscopy (TEM analysis confirmed the deposition of highly dispersed Pt nanoparticles with sizes determined by the MIL-101-Cr pore sizes and with an increased Pt loading for an increasing number of ALD cycles. The Pt@MIL-101 material was examined as catalyst in the hydrogenation of different linear and cyclic olefins at room temperature, showing full conversion for each substrate. Moreover, even under solvent free conditions, full conversion of the substrate was observed. A high concentration test has been performed showing that the Pt@MIL-101 is stable for a long reaction time without loss of activity, crystallinity and with very low Pt leaching.

  3. Reduction of Ordering Temperature of FePt Al2O3 Thin Films by N2 Addition During Sputtering

    Science.gov (United States)

    Cao, Jiang-Wei; Katayama, N.; Yang, Zheng; Wei, Fu-Lin; Matsumoto, M.; Morisako, A.; Liu, Xiao-Xi; Takei, S.

    2005-11-01

    We investigate the effect of N2 addition during sputtering on the microstructure and magnetic properties of FePt-Al2O3 thin films. The texture of FePt phase in FePt-Al2O3 thin films changes from (111) to a more random orientation by N2 addition during sputtering. The ordering temperature of FePt phase reduces about 100°C with appropriate N2 partial pressure. A larger coercivity of 6.0×105 A/m is obtained with N2 partial pressure about 15%. Structural analysis reveals that a small quantity of Fe3N phase forms during sputtering and the release of N atoms during the post annealing induces a large number of vacancies in the films, which benefits to the transformation of FePt phase from fcc to fct.

  4. Methanol oxidation on carbon supported Pt-Ru catalysts prepared by electrodeposition - Evaluation of Nafion {sup registered} 117 film effect

    Energy Technology Data Exchange (ETDEWEB)

    Sieben, J.M. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur, Av. Alem 1253 (B8000CPB) Bahia Blanca, Buenos Aires (Argentina); Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur, Av. Alem 1253 (B8000CPB) Bahia Blanca, Buenos Aires (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC) (Argentina)

    2010-03-15

    Diverse electrochemical techniques were performed in order to obtain meaningful information about the methanol oxidation reaction on nanostructured planar carbon supported Pt-Ru electrodes prepared by electrodeposition, on which a layer of Nafion ionomer was incorporated. A metallic deposit consisting of dendritic agglomerates (between 50 and 200 nm) constituted by smaller particles (6 nm) was obtained. The average bulk Ru content obtained by EDX analysis was between 23 and 25 at. %. A decrease of the activity in the electrodes for methanol oxidation was determined when the thickness of the Nafion 117 film was increased. These results may be associated with the partial blocking of the surface active sites by hydrophobic domains of the polymer, and the presence of CO{sub 2} molecules retained within the Nafion hydrophilic microchannels. EIS results indicated that methanol electro-oxidation mechanism does not change with Nafion presence. (author)

  5. The effect of growth surface morphology on the crystal structure and magnetic property of L1{sub 0} order PtFe layers deposited by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ding Wanyu, E-mail: dwysd_2000@163.com [Graduate School of Saitama Institute of Technology, Fukaya, Saitama 369-0293 (Japan) and School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Ishiguro, Satoshi; Ogatsu, Ryo [Graduate School of Saitama Institute of Technology, Fukaya, Saitama 369-0293 (Japan); Ju, Dongying, E-mail: dyju@sit.ac.jp [Graduate School of Saitama Institute of Technology, Fukaya, Saitama 369-0293 (Japan)

    2012-08-01

    The Fe/Pt/Fe/Pt layers (Pt/Fe multilayer) were deposited on general glass substrate at room temperature by magnetron sputtering technique. Varying the deposition and post-annealing treatment parameters, the PtFe alloy (PtFe) layer with different crystal structures and magnetic properties were obtained at the interface between Fe and Pt layer. The characterization by X-ray diffraction (XRD) showed that the as-deposited Pt/Fe multilayer only contained pure Fe and Pt with body-centered and face-centered cubic structures, respectively. As-deposited Pt layer displayed (2 0 0) preferred orientation, and the columnar grains structure could be observed by the scanning electron microscopy. The PtFe layers with L1{sub 0} face-centered cubic structure could be formed at the interface between Pt and Fe layers by post-annealing the multilayers at 500 Degree-Sign C. In case of Pt/Fe multilayer deposited on smooth substrate, the larger columnar grains in Pt layer resulted in L1{sub 0} PtFe layers without any preferred orientation. While in case of Pt/Fe multilayer deposited on the rough substrate, the thinner columnar grains in Pt layer could induce L1{sub 0} PtFe layers with (2 0 0) preferred orientation. In this case, the vibrating sample magnetometer results indicated that, the magnetic coercivity in plane and out-of-plane model could reach 3.72 and 2.32 kOe, respectively. Based on above results, the L1{sub 0} structure Pt/Fe multilayer with satisfied magnetic properties could be prepared at low temperature by our simple route.

  6. Chemical vapor deposition reactor. [providing uniform film thickness

    Science.gov (United States)

    Chern, S. S.; Maserjian, J. (Inventor)

    1977-01-01

    An improved chemical vapor deposition reactor is characterized by a vapor deposition chamber configured to substantially eliminate non-uniformities in films deposited on substrates by control of gas flow and removing gas phase reaction materials from the chamber. Uniformity in the thickness of films is produced by having reactive gases injected through multiple jets which are placed at uniformally distributed locations. Gas phase reaction materials are removed through an exhaust chimney which is positioned above the centrally located, heated pad or platform on which substrates are placed. A baffle is situated above the heated platform below the mouth of the chimney to prevent downdraft dispersion and scattering of gas phase reactant materials.

  7. Aluminosilicate glass thin films elaborated by pulsed laser deposition

    Science.gov (United States)

    Carlier, Thibault; Saitzek, Sébastien; Méar, François O.; Blach, Jean-François; Ferri, Anthony; Huvé, Marielle; Montagne, Lionel

    2017-03-01

    In the present work, we report the elaboration of aluminosilicate glass thin films by Pulsed Laser Deposition at various temperatures deposition. The amorphous nature of glass thin films was highlighted by Grazing Incidence X-Ray Diffraction and no nanocristallites were observed in the glassy matrix. Chemical analysis, obtained with X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy, showed a good transfer and homogeneous elementary distribution with of chemical species from the target to the film a. Structural studies performed by Infrared Spectroscopy showed that the substrate temperature plays an important role on the bonding configuration of the layers. A slight shift of Si-O modes to larger wavenumber was observed with the synthesis temperature, assigned to a more strained sub-oxide network. Finally, optical properties of thins film measured by Spectroscopic Ellipsometry are similar to those of the bulk aluminosilicate glass, which indicate a good deposition of aluminosilicate bulk glass.

  8. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    Energy Technology Data Exchange (ETDEWEB)

    Exner, Jörg, E-mail: Functional.Materials@Uni-Bayreuth.de [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany); Fuierer, Paul [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Moos, Ralf [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany)

    2014-12-31

    Bismuth vanadate, Bi{sub 4}V{sub 2}O{sub 11}, and related compounds with various metal (Me) substitutions, Bi{sub 4}(Me{sub x}V{sub 1−x}){sub 2}O{sub 11−δ}, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated.

  9. Picosecond and subpicosecond pulsed laser deposition of Pb thin films

    Directory of Open Access Journals (Sweden)

    F. Gontad

    2013-09-01

    Full Text Available Pb thin films were deposited on Nb substrates by means of pulsed laser deposition (PLD with UV radiation (248 nm, in two different ablation regimes: picosecond (5 ps and subpicosecond (0.5 ps. Granular films with grain size on the micron scale have been obtained, with no evidence of large droplet formation. All films presented a polycrystalline character with preferential orientation along the (111 crystalline planes. A maximum quantum efficiency (QE of 7.3×10^{-5} (at 266 nm and 7 ns pulse duration was measured, after laser cleaning, demonstrating good photoemission performance for Pb thin films deposited by ultrashort PLD. Moreover, Pb thin film photocathodes have maintained their QE for days, providing excellent chemical stability and durability. These results suggest that Pb thin films deposited on Nb by ultrashort PLD are a noteworthy alternative for the fabrication of photocathodes for superconductive radio-frequency electron guns. Finally, a comparison with the characteristics of Pb films prepared by ns PLD is illustrated and discussed.

  10. UV laser deposition of metal films by photogenerated free radicals

    Science.gov (United States)

    Montgomery, R. K.; Mantei, T. D.

    1986-01-01

    A novel photochemical method for liquid-phase deposition of metal films is described. In the liquid phase deposition scheme, a metal containing compound and a metal-metal bonded carbonyl complex are dissolved together in a polar solvent and the mixture is irradiated using a UV laser. The optical arrangement consists of a HeCd laser which provides 7 mW of power at a wavelength of 325 nm in the TEM(OO) mode. The beam is attenuated and may be expanded to a diameter of 5-20 mm. Experiments with photochemical deposition of silver films onto glass and quartz substrates are described in detail. Mass spectrometric analysis of deposited silver films indicated a deposition rate of about 1 A/s at incident power levels of 0.01 W/sq cm. UV laser-induced copper and palladium films have also been obtained. A black and white photograph showing the silver Van Der Pauw pattern of a solution-deposited film is provided.

  11. Microreactor-Assisted Solution Deposition for Compound Semiconductor Thin Films

    Directory of Open Access Journals (Sweden)

    Chang-Ho Choi

    2014-05-01

    Full Text Available State-of-the-art techniques for the fabrication of compound semiconductors are mostly vacuum-based physical vapor or chemical vapor deposition processes. These vacuum-based techniques typically operate at high temperatures and normally require higher capital costs. Solution-based techniques offer opportunities to fabricate compound semiconductors at lower temperatures and lower capital costs. Among many solution-based deposition processes, chemical bath deposition is an attractive technique for depositing semiconductor films, owing to its low temperature, low cost and large area deposition capability. Chemical bath deposition processes are mainly performed using batch reactors, where all reactants are fed into the reactor simultaneously and products are removed after the processing is finished. Consequently, reaction selectivity is difficult, which can lead to unwanted secondary reactions. Microreactor-assisted solution deposition processes can overcome this limitation by producing short-life molecular intermediates used for heterogeneous thin film synthesis and quenching the reaction prior to homogeneous reactions. In this paper, we present progress in the synthesis and deposition of semiconductor thin films with a focus on CdS using microreactor-assisted solution deposition and provide an overview of its prospect for scale-up.

  12. Growth of oblique sputtered Co and CoCrPt thin films for high-density tape recording

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, L.T. [System and Materials for Information Storage Group, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); Tichelaar, F.D. [Faculty of Applied Sciences, National Center for High Resolution Electron Microscopy, Kavli Institute of Nanoscience, Technical University of Delf, Rotterdamseweg 137, 2628Al Delf (Netherlands); Lodder, J.C. [System and Materials for Information Storage Group, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands)]. E-mail: j.c.lodder@el.utwente.nl

    2005-04-15

    In this paper, we report the properties of Co/Cr and CoCrPt/CoCrMn thin films grown by oblique sputtering onto polymer substrates. It is observed that in both cases, the underlayers promote the formation of HCP-structure of the magnetic layers, which results in a high magnetic anisotropy of the films consequently, high coercivities of 200 and 300 kA/m are obtained in the 20 nm Co/180 nm Cr and 30 nm CoCrPt/50 nm CoCrMn films, respectively. However, in the case of Co/Cr film, Co grains are relatively large and elongated following the transverse direction while in the case of CoCrPt/CoCrMn film, a tiny columnar structure inclined toward the incident direction is observed. This fact results in a different magnetic behavior of these films.

  13. Effect of a Boron Underlayer on the Ordering and Orientation of Sputtered FePt Film

    Institute of Scientific and Technical Information of China (English)

    LI Yong-Le; HUANG An-Ping; FENG Tang-Fu; CHEN Qiang; SHU Xiao-Lin; CHEN Jun-Yang; CHEN Zi-Yu

    2011-01-01

    @@ FePt multilayer films with a boron underlayer are prepared on Si (100) substrates using magnetron sputtering and vacuum annealing is carried out to obtain the hard magnetic Llo phase.According to the microstructural and magnetic measurement results, the ordering of the FePt films is facilitated at low annealing temperatures while it is blocked at high ones by introducing boron.Moreover, (001) orientation of the samples is obviously improved by inserting a boron underlayer, which is further confirmed by the MFM analysis.The relevant mechanism is discussed by considering the diffusion of boron atoms and the consequential in-plane tensile stress.%FePt multilayer Sims with a boron underlayer are prepared on Si (100) substrates using magnetron sputtering and vacuum annealing is carried out to obtain the hard magnetic Llo phase. According to the microstructural and magnetic measurement results, the ordering of the FePt 61ms is facilitated at low annealing temperatures while it is blocked at high ones by introducing boron. Moreover, (001) orientation of the samples is obviously improved by inserting a boron underlayer, which is further confirmed by the MFM analysis. The relevant mechanism is discussed by considering the diffusion of boron atoms and the consequential in-plane tensile stress.

  14. Abnormal temperature dependence of the coercive field in FePt thin films

    Energy Technology Data Exchange (ETDEWEB)

    Guzmán, J.M. [Facultad de Ciencias Químicas – Universidad Nacional de Córdoba – 5000 Córdoba (Argentina); Álvarez, N.; Salva, H.R.; Vásquez Mansilla, M.; Gómez, J. [Centro Atómico Bariloche (CNEA), Instituto Balseiro (U. N. Cuyo) and Conicet, 8400 Bariloche, Río Negro (Argentina); Butera, A., E-mail: butera@cab.cnea.gov.ar [Centro Atómico Bariloche (CNEA), Instituto Balseiro (U. N. Cuyo) and Conicet, 8400 Bariloche, Río Negro (Argentina)

    2013-12-15

    We have observed notable changes in the magnetic response of FePt thin films that we have attributed to a transition in the magnetic domain structure when the film thickness or the temperature is varied. The critical thickness for this transition depends on the Q-factor, Q=K{sub ⊥}/2πM{sub s}{sup 2}, so that a change in the domain structure is expected when changes in the perpendicular anisotropy, K{sub ⊥}, or the saturation magnetization, M{sub s}, occur. At room temperature these samples have Q∼0.3, and a transition between planar to stripe-like domains occurs for a film thickness d∼30nm. Due to the different thermal expansion of the FePt alloy and the Si substrate a reduction in Q is predicted when the temperature is lowered. From magnetization vs. field loops measured at different temperatures below T=300 K, we have effectively observed a change in the coercive field which can be associated to a transition from stripe-like to in-plane domains. The transition temperature range is broad, indicating a gradual variation between the two magnetic configurations, but changes systematically with film thickness, consistent with an interfacial induced stress. A model that includes the temperature dependence of the strain and the magnetization, predicts correctly the observation of a larger critical thickness at lower temperatures. - Highlights: • The magnetic domain configuration of disordered FePt films can be thermally switched between in-plane domains and stripe domains. • Results are explained by considering the full temperature dependence of the induced stress which produces an out-of-plane anisotropy axis. • The transition temperature changes systematically with film thickness, consistent with an interfacial induced stress.

  15. Underpotential deposition of hydrogen on benzene-modified Pt(111) in aqueous H2SO4.

    Science.gov (United States)

    Jerkiewicz, Gregory; DeBlois, Martin; Radovic-Hrapovic, Zorana; Tessier, Jean-Pierre; Perreault, Frédéric; Lessard, Jean

    2005-04-12

    The Pt(111) electrode is modified by an overlayer of C6H6 (ads) upon its cycling in the 0.05-0.80 V range in aq H2SO4 + 1 mM C6H6. The C6H6 (ads) overlayer significantly changes the underpotential-deposited H (H(UPD)) and anion adsorption, and cyclic-voltammetry (CV) profiles show a sharp cathodic peak and an asymmetric anodic one in the 0.05-0.80 V potential range. The C6H6 (ads) layer blocks the (bi)sulfate adsorption but facilitates the adsorption of one monolayer of H(UPD). Cycling of the benzene-modified Pt(111) in benzene-free aq 0.05 H2SO4 from 0.05 to 0.80 V results in a partial desorption of C6H6 (ads) and in a partial recovery of the CV profile characteristic of an unmodified Pt(111). The peak potential of the cathodic and anodic feature is independent of the scan rate, s (10 0 to 0 kJ mol(-1) at theta(H(UPD) --> 1. The nonzero values of delta Delta G degrees testify that the adsorbing and desorbing H(UPD) adatoms interact with an energetically different substrate. The lateral interactions changed from repulsive (omega = 29 kJ mol(-1) at theta(H(UPD) --> 0) to attractive (omega = -28 kJ mol(-1) at theta(H(UPD) --> 1) as the H(UPD) coverage increases. The values of delta S degrees(ads)(H(UPD)) increase from 19 to 56 J K(-1) mol(-1), while those of delta S degrees(des)(H(UPD)) decrease from 45 to -30 J K(-1) mol(-1) with an increase of H(UPD) coverage. The values of delta H degrees(des)(H(UPD)) and delta H degrees(des)(H(UPD)) vary from 0 to 27 kJ mol(-1). The Pt(111)-H(UPD) surface bond energy at the benzene-modified Pt(111) electrode falls in the 191-218 kJ mol(-1) range and is weaker than in the case of the unmodified Pt(111) electrode in the same electrolyte.

  16. Underpotential deposition-induced synthesis of composition-tunable Pt-Cu nanocrystals and their catalytic properties.

    Science.gov (United States)

    Jiang, Yaqi; Jia, Yanyan; Zhang, Jiawei; Zhang, Lei; Huang, Huang; Xie, Zhaoxiong; Zheng, Lansun

    2013-02-25

    Pt-Cu alloy octahedral nanocrystals (NCs) have been synthesized successfully by using N,N-dimethylformamide as both the solvent and the reducing agent in the presence of cetyltrimethylammonium chloride. Cu underpotential deposition (UPD) is found to play a key role in the formation of the Pt-Cu alloy NCs. The composition in the Pt-Cu alloy can be tuned by adjusting the ratio of metal precursors in solution. However, the Cu content in the Pt-Cu alloy NCs cannot exceed 50%. Due to the fact that Cu precursor cannot be reduced to metallic copper and the Cu content cannot exceed 50%, we achieved the formation of the Pt-Cu alloy by using Cu UPD on the Pt surface. In addition, the catalytic activities of Pt-Cu alloy NCs with different composition were investigated in electrocatalytic oxidation of formic acid. The results reveal that the catalytic performance is strongly dependent on Pt-Cu alloy composition. The sample of Pt(50)Cu(50) exhibits excellent activity in electrocatalytic oxidation of formic acid.

  17. High-quality AlN films grown on chemical vapor-deposited graphene films

    Directory of Open Access Journals (Sweden)

    Chen Bin-Hao

    2016-01-01

    Full Text Available We report the growth of high-quality AlN films on graphene. The graphene films were synthesized by CVD and then transferred onto silicon substrates. Epitaxial aluminum nitride films were deposited by DC magnetron sputtering on both graphene as an intermediate layer and silicon as a substrate. The structural characteristics of the AlN films and graphene were investigated. Highly c-axis-oriented AlN crystal structures are investigated based on the XRDpatterns observations.

  18. Preparation of AuPt alloy foam films and their superior electrocatalytic activity for the oxidation of formic acid.

    Science.gov (United States)

    Liu, Jun; Cao, Ling; Huang, Wei; Li, Zelin

    2011-09-01

    AuPt alloy films with three-dimensional (3D) hierarchical pores consisting of interconnected dendrite walls were successfully fabricated by a strategy of cathodic codeposition utilizing the hydrogen bubble dynamic template. The foam films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Due to the special porous structure, the electronic property, and the assembly effect, the AuPt alloy foam films show superior electrocatalytic activity toward the electrooxidation of formic acid in acidic solution, and the prepared 3D porous AuPt alloy films also show high activity and long stability for the electrocatalytic oxidation of methanol, where synergistic effect plays an important role in addition to the electronic effect and assembly effect. These findings provide more insights into the AuPt bimetallic nanomaterials for electrocatalytic applications.

  19. Large-Scale Graphene Film Deposition for Monolithic Device Fabrication

    Science.gov (United States)

    Al-shurman, Khaled

    Since 1958, the concept of integrated circuit (IC) has achieved great technological developments and helped in shrinking electronic devices. Nowadays, an IC consists of more than a million of compacted transistors. The majority of current ICs use silicon as a semiconductor material. According to Moore's law, the number of transistors built-in on a microchip can be double every two years. However, silicon device manufacturing reaches its physical limits. To explain, there is a new trend to shrinking circuitry to seven nanometers where a lot of unknown quantum effects such as tunneling effect can not be controlled. Hence, there is an urgent need for a new platform material to replace Si. Graphene is considered a promising material with enormous potential applications in many electronic and optoelectronics devices due to its superior properties. There are several techniques to produce graphene films. Among these techniques, chemical vapor deposition (CVD) offers a very convenient method to fabricate films for large-scale graphene films. Though CVD method is suitable for large area growth of graphene, the need for transferring a graphene film to silicon-based substrates is required. Furthermore, the graphene films thus achieved are, in fact, not single crystalline. Also, graphene fabrication utilizing Cu and Ni at high growth temperature contaminates the substrate that holds Si CMOS circuitry and CVD chamber as well. So, lowering the deposition temperature is another technological milestone for the successful adoption of graphene in integrated circuits fabrication. In this research, direct large-scale graphene film fabrication on silicon based platform (i.e. SiO2 and Si3N4) at low temperature was achieved. With a focus on low-temperature graphene growth, hot-filament chemical vapor deposition (HF-CVD) was utilized to synthesize graphene film using 200 nm thick nickel film. Raman spectroscopy was utilized to examine graphene formation on the bottom side of the Ni film

  20. Electrodynamic properties of porous PZT-Pt films at terahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Komandin, Gennady A.; Porodinkov, Oleg E.; Spektor, Igor E.; Volkov, Alexander A. [Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Vorotilov, Konstantin A.; Seregin, Dmitry S.; Sigov, Alexander S. [Moscow Technological University (MIREA), Moscow (Russian Federation)

    2017-01-15

    Electrodynamics of Si-SiO{sub 2}-TiO{sub 2}-Pt-PZT heterostructures is studied in the frequency range from 5 to 5000 cm{sup -1} by monochromatic BWO (backward wave oscillator) and infrared Fourier-transform spectroscopy techniques to derive the dielectric characteristics of the sol-gel porous ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} films. Broad frequency band dielectric response of PZT films with different density is constructed using the oscillator dispersion models. The main contribution to the film permittivity is found to form at frequencies below 100 cm{sup -1} depending strongly and non-linearly on the film medium density. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Martinez-Landeros, V. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Mejia, I. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Nascimento, C.D.; Azevedo, G. de M; Krug, C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91509-900 (Brazil); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States)

    2014-01-01

    The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10{sup −1} to 10{sup 4} Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10{sup 19} to 10{sup 13} cm{sup −3} and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm{sup 2}/V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10{sup 19} to 10{sup 13} cm{sup −3}. • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied.

  2. Asymmetric magnetic bubble expansion under in-plane field in Pt/Co/Pt : Effect of interface engineering

    NARCIS (Netherlands)

    Lavrijsen, R.; Hartmann, D. M. F.; van den Brink, Ton; Yin, Y.; Barcones, B.; Duine, R. A.|info:eu-repo/dai/nl/304830127; Verheijen, M. A.; Swagten, H. J. M.; Koopmans, B.

    2015-01-01

    We analyze the impact of growth conditions on the asymmetric magnetic bubble expansion under an in-plane field in ultrathin Pt/Co/Pt films. Specifically, using sputter deposition, we vary the Ar pressure during the growth of the top Pt layer. This induces a large change in the interfacial structure

  3. Asymmetric magnetic bubble expansion under in-plane field in Pt/Co/Pt : Effect of interface engineering

    NARCIS (Netherlands)

    Lavrijsen, R.; Hartmann, D. M. F.; van den Brink, Ton; Yin, Y.; Barcones, B.; Duine, R. A.; Verheijen, M. A.; Swagten, H. J. M.; Koopmans, B.

    2015-01-01

    We analyze the impact of growth conditions on the asymmetric magnetic bubble expansion under an in-plane field in ultrathin Pt/Co/Pt films. Specifically, using sputter deposition, we vary the Ar pressure during the growth of the top Pt layer. This induces a large change in the interfacial structure

  4. Strain-coupled multiferroic model system of magnetic films on piezoelectric PMN-PT(001)

    Energy Technology Data Exchange (ETDEWEB)

    Herklotz, Andreas; Rata, Diana; Boldyreva, Ksenia; Bilani-Zeneli, Orkidia; Dekker, Martina Cornelia; Schultz, Ludwig; Doerr, Kathrin [IFW Dresden (Germany)

    2009-07-01

    In many multiferroic composites the interrelation of magnetic and polar electric properties originates from joined elastic strain of the components. A straightforward model system for quantitative investigations of strain-modulated magnetic properties comprises of magnetic films epitaxially grown on high-strain piezoelectric single crystals. In this work, we report on structural, ferroelectric and elastic properties of Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PMN-PT) (001) single crystals utilized as thin film substrates for dynamical strain control of up to 0.25% in complex oxide films. A tunable buffer layer system of solid solutions of perovskite-type LaScO{sub 3} and LaAlO{sub 3} has been developed that serves to adjust the in-plane parameter of buffered PMN-PT in a range of several percent. Thus, various as-grown strain states of a given magnetic film can be prepared and studied under reversible strain. First examples for La{sub 1-x}Sr{sub x}BO{sub 3} (B=Co or Mn) films under both statically and dynamically varied biaxial strain will be discussed.

  5. Improving the Ethanol Oxidation Activity of Pt-Mn Alloys through the Use of Additives during Deposition

    Directory of Open Access Journals (Sweden)

    Mohammadreza Zamanzad Ghavidel

    2015-06-01

    Full Text Available In this work, sodium citrate (SC was used as an additive to control the particle size and dispersion of Pt-Mn alloy nanoparticles deposited on a carbon support. SC was chosen, since it was the only additive tested that did not prevent Mn from co-depositing with Pt. The influence of solution pH during deposition and post-deposition heat treatment on the physical and electrochemical properties of the Pt-Mn alloy was examined. It was determined that careful control over pH is required, since above a pH of four, metal deposition was suppressed. Below pH 4, the presence of sodium citrate reduced the particle size and improved the particle dispersion. This also resulted in larger electrochemically-active surface areas and greater activity towards the ethanol oxidation reaction (EOR. Heat treatment of catalysts prepared using the SC additive led to a significant enhancement in EOR activity, eclipsing the highest activity of our best Pt-Mn/C prepared in the absence of SC. XRD studies verified the formation of the Pt-Mn intermetallic phase upon heat treatment. Furthermore, transmission electron microscopy studies revealed that catalysts prepared using the SC additive were more resistant to particle size growth during heat treatment.

  6. Effect of aging and annealing on perpendicular magnetic anisotropy of ultra-thin CoPt films

    Science.gov (United States)

    Hara, R.; Hayakawa, K.; Ebata, K.; Sugita, R.

    2016-05-01

    The effect of aging and annealing on the magnetic properties of ultra-thin CoPt films with a Ru underlayer was investigated. For the 3 nm thick CoPt film aged in the air, the decrease of the saturation magnetic moment ms, the drastic increase of the perpendicular coercivity Hc⊥ and the perpendicular anisotropy were observed. This is because the surface layer of the CoPt film was oxidized and the bottom layer with high perpendicular anisotropy due to lattice distortion remained. For the annealed 3 nm thick CoPt film with a Pt protective layer, rising the annealing temperature Ta led to the decrease of ms, the decrease after increase of Hc⊥, and the decrease of the perpendicular squareness ratio S⊥ at Ta of 400 ∘C. The origins of effect of annealing were considered to be the grain boundary diffusion and the bulk diffusion of Ru and Pt into the CoPt film, and relaxation of the lattice distortion.

  7. Effect of aging and annealing on perpendicular magnetic anisotropy of ultra-thin CoPt films

    Directory of Open Access Journals (Sweden)

    R. Hara

    2016-05-01

    Full Text Available The effect of aging and annealing on the magnetic properties of ultra-thin CoPt films with a Ru underlayer was investigated. For the 3 nm thick CoPt film aged in the air, the decrease of the saturation magnetic moment ms, the drastic increase of the perpendicular coercivity Hc⊥ and the perpendicular anisotropy were observed. This is because the surface layer of the CoPt film was oxidized and the bottom layer with high perpendicular anisotropy due to lattice distortion remained. For the annealed 3 nm thick CoPt film with a Pt protective layer, rising the annealing temperature Ta led to the decrease of ms, the decrease after increase of Hc⊥, and the decrease of the perpendicular squareness ratio S⊥ at Ta of 400 ∘C. The origins of effect of annealing were considered to be the grain boundary diffusion and the bulk diffusion of Ru and Pt into the CoPt film, and relaxation of the lattice distortion.

  8. High-quality graphene grown on polycrystalline PtRh{sub 20} alloy foils by low pressure chemical vapor deposition and its electrical transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Yang, He; Shen, Chengmin, E-mail: cmshen@iphy.ac.cn; Tian, Yuan; Bao, Lihong; Chen, Peng; Yang, Rong; Yang, Tianzhong; Li, Junjie; Gu, Changzhi; Gao, Hong-Jun [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2016-02-08

    High-quality continuous uniform monolayer graphene was grown on polycrystalline PtRh{sub 20} alloy foils by low pressure chemical vapor deposition. The morphology of graphene was investigated by Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. Analysis results confirm that high quality single-layer graphene was fabricated on PtRh{sub 20} foil at 1050 °C using a lower flux of methane under low pressure. Graphene films were transferred onto the SiO{sub 2}/Si substrate by the bubbling transfer method. The mobility of a test field effect transistor made of the graphene grown on PtRh{sub 20} was measured and reckoned at room temperature, showing that the carrier mobility was about 4000 cm{sup 2} V{sup −1} s{sup −1}. The results indicate that desired quality of single-layer graphene grown on PtRh{sub 20} foils can be obtained by tuning reaction conditions.

  9. Controlled deposition and enhanced visible light photocatalytic performance of Pt-modified TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Jun, E-mail: lvjun117@126.com [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Gao, Huazhen; Wang, Honge; Lu, Xuejun; Xu, Guangqing; Wang, Dongmei [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, Zhong [School of Materials Science and Engineering, Nanyang Technological University (Singapore); Zhang, Xinyi [School of Chemistry, Monash University, Clayton, Vic. 3800 (Australia); Zheng, Zhixiang [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China)

    2015-10-01

    Graphical abstract: - Highlights: • Pt nanoparticles were deposited onto TiO{sub 2} NTAs by UV light photoreduction method. • Uniform distribution of nanoparticles was achieved by controlling deposition. • 3 Pt/TiO{sub 2} NTAs show 84.27% degradation rate after visible light irradiation. • The kinetic constant of 3 Pt/TiO{sub 2} NTAs is 0.01493 min{sup −1}. - Abstract: Highly ordered TiO{sub 2} nanotube arrays (TiO{sub 2} NTAs) have been fabricated by the potentiostatic anodization method with Ti foils. Pt nanoparticles have been successfully deposited onto TiO{sub 2} NTAs by UV light photoreduction method. In this work, X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy and energy dispersive X-ray spectrometer methods were adopted to characterize the samples. The influence of different concentration of H{sub 2}PtCl{sub 6} precursor solution on the morphology and photocatalytic performances of samples was discussed. The SEM observations showed that Pt nanoparticles distributed on the wall of TiO{sub 2} nanotubes uniformly. UV–vis spectra analysis showed that the light absorption of Pt/TiO{sub 2} NTAs has been extended to the visible light range. When the concentration of H{sub 2}PtCl{sub 6} was 3 mM, the prepared sample showed the highest photodegradation rate. After irradiated under visible light for 2 h, the degradation rate of methyl orange solution reached 84.27%. Under the same condition, no obvious photodegradation of methyl orange was found for TiO{sub 2} NTAs. Kinetic research showed that photodegradation process followed the first-order reaction, the apparent reaction rate constant of 3 Pt/TiO{sub 2} NTAs was 1.493 × 10{sup −2} min{sup −1}.

  10. Growth of tantalum pentoxide film by pulsed laser deposition

    Science.gov (United States)

    Zhang, Jun-Ying; Fang, Qi; Boyd, Ian W.

    1999-01-01

    Thin films of Ta 2O 5 have been deposited on quartz and silicon substrates by 532-nm (Nd:YAG) pulsed laser deposition (PLD) in various O 2 gas environments. The influence of the deposition parameters, such as oxygen pressure, substrate temperature and annealing under UV irradiation using a 172-nm excimer lamp, on the properties of the grown films, has been studied. The refractive index of the films increases with increasing pressure of O 2. X-ray diffraction measurements show that the as-deposited films are amorphous at temperatures below 500°C and possess orthorhombic (β-Ta 2O 5) crystal structure at temperatures above 600°C. The optical properties determined by UV spectrophotometry also strongly depend on the deposition parameters. At O 2 pressures above 0.15 mbar, the refractive index of the films was about 2.12 which is close to the bulk Ta 2O 5 value of 2.2. Optical transmittance around 85% in the visible region of the spectrum was obtained at an oxygen pressure of 0.2 mbar.

  11. Pulsed laser deposition of niobium nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Farha, Ashraf Hassan, E-mail: ahass006@odu.edu; Elsayed-Ali, Hani E., E-mail: helsayed@odu.edu [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529 (United States); Applied Research Center, Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566 (Egypt); Ufuktepe, Yüksel, E-mail: ufuk@cu.edu.tr [Department of Physics, University of Cukurova, 01330 Adana (Turkey); Myneni, Ganapati, E-mail: rao@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2015-12-04

    Niobium nitride (NbN{sub x}) films were grown on Nb and Si(100) substrates using pulsed laser deposition. NbN{sub x} films were deposited on Nb substrates using PLD with a Q-switched Nd:YAG laser (λ = 1064 nm, ∼40 ns pulse width, and 10 Hz repetition rate) at different laser fluences, nitrogen background pressures and deposition substrate temperatures. When all the fabrication parameters are fixed, except for the laser fluence, the surface roughness, nitrogen content, and grain size increase with increasing laser fluence. Increasing nitrogen background pressure leads to a change in the phase structure of the NbN{sub x} films from mixed β-Nb{sub 2}N and cubic δ-NbN phases to single hexagonal β-Nb{sub 2}N. The substrate temperature affects the preferred orientation of the crystal structure. The structural and electronic, properties of NbN{sub x} deposited on Si(100) were also investigated. The NbN{sub x} films exhibited a cubic δ-NbN with a strong (111) orientation. A correlation between surface morphology, electronic, and superconducting properties was found. The observations establish guidelines for adjusting the deposition parameters to achieve the desired NbN{sub x} film morphology and phase.

  12. Visible-light active thin-film WO3 photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    Directory of Open Access Journals (Sweden)

    Nobuto Oka

    2015-10-01

    Full Text Available A process based on reactive gas flow sputtering (GFS for depositing visible-light active photocatalytic WO3 films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO3 films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH3CHO under visible light irradiation. The decomposition time for 60 ppm of CH3CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO3 films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH3CHO.

  13. Epitaxial yttrium iron garnet films grown by pulsed laser deposition

    Science.gov (United States)

    Dorsey, P. C.; Bushnell, S. E.; Seed, R. G.; Vittoria, C.

    1993-07-01

    Epitaxial Y3Fe5O12 (YIG) films have been grown by the pulsed laser deposition (PLD) technique on (111) gadolinium gallium garnet substrates. The effect of substrate temperature and oxygen partial pressure on the structure, composition, and magnetic properties of the films was investigated and compared to liquid phase epitaxy YIG films. The results demonstrated that epitaxial YIG films could be prepared under a wide range of deposition conditions, but narrow linewidth (ΔH≂1 Oe) films were producible only at low oxygen partial pressures (O2temperatures (Ts≳800 °C). Since the linewidth of single-crystal YIG is dominated by surface and volume defects and/or impurities, the narrow linewidth indicated that PLD is a viable technique for producing high-quality ferrite films for microwave device applications. In addition, under all deposition conditions (50-1000 mTorr and 700-850 °C) there is a uniaxial axis perpendicular to the film plane. However, at low oxygen pressure the uniaxial anisotropy energy constant Ku is negative while at high oxygen pressure Ku is positive.

  14. CdS films deposited by chemical bath under rotation

    Energy Technology Data Exchange (ETDEWEB)

    Oliva-Aviles, A.I., E-mail: aoliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico); Patino, R.; Oliva, A.I. [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico)

    2010-08-01

    Cadmium sulfide (CdS) films were deposited on rotating substrates by the chemical bath technique. The effects of the rotation speed on the morphological, optical, and structural properties of the films were discussed. A rotating substrate-holder was fabricated such that substrates can be taken out from the bath during the deposition. CdS films were deposited at different deposition times (10, 20, 30, 40 and 50 min) onto Corning glass substrates at different rotation velocities (150, 300, 450, and 600 rpm) during chemical deposition. The chemical bath was composed by CdCl{sub 2}, KOH, NH{sub 4}NO{sub 3} and CS(NH{sub 2}){sub 2} as chemical reagents and heated at 75 deg. C. The results show no critical effects on the band gap energy and the surface roughness of the CdS films when the rotation speed changes. However, a linear increase on the deposition rate with the rotation energy was observed, meanwhile the stoichiometry was strongly affected by the rotation speed, resulting a better 1:1 Cd/S ratio as speed increases. Rotation effects may be of interest in industrial production of CdTe/CdS solar cells.

  15. Research of special carbon nanobeads supported Pt catalyst for fuel cell through high temperature pyrolysis and deposition from novel phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    GUO Yanchuan; YUE Jun; PAN Zhongxiao; XU Haitao; ZHANG Bing; HAN Fengmei; CHEN Lijuan; PENG Bixian; XIE Wenwei; QIAN Haisheng; YAN Tiantang

    2004-01-01

    The carbon nanobeads were prepared through high temperature pyrolysis and deposition from phthaiocyanine. After surface's functionalization treatment of the carbon beads, the carbon nanobeads supported Pt catalyst was produced. The Pt/C catalyst was characterized by SEM,TEM, Raman spectrum, EDS and XRD methods. Combining the carbonaceous paper spreaded up with the catalyst with Nafion membrane, we made MEA electrode. The discharge curves indicated that this carbon nanobeads supported Pt is a good fuel cell catalyst with excellent performance, high activity and sign of a long-time life.

  16. Characterization of Pt@Cu Core@Shell Dendrimer-Encapsulated Nanoparticles Synthesized by Cu Underpotential Deposition

    Energy Technology Data Exchange (ETDEWEB)

    E Carino; R Crooks

    2011-12-31

    Dendrimer-encapsulated nanoparticles (DENs) containing averages of 55, 147, and 225 Pt atoms immobilized on glassy carbon electrodes served as the electroactive surface for the underpotential deposition (UPD) of a Cu monolayer. This results in formation of core@shell (Pt@Cu) DENs. Evidence for this conclusion comes from cyclic voltammetry, which shows that the Pt core DENs catalyze the hydrogen evolution reaction before Cu UPD, but that after Cu UPD this reaction is inhibited. Results obtained by in situ electrochemical X-ray absorption spectroscopy (XAS) confirm this finding.

  17. Characterization of Pt@Cu core@shell dendrimer-encapsulated nanoparticles synthesized by Cu underpotential deposition.

    Science.gov (United States)

    Carino, Emily V; Crooks, Richard M

    2011-04-05

    Dendrimer-encapsulated nanoparticles (DENs) containing averages of 55, 147, and 225 Pt atoms immobilized on glassy carbon electrodes served as the electroactive surface for the underpotential deposition (UPD) of a Cu monolayer. This results in formation of core@shell (Pt@Cu) DENs. Evidence for this conclusion comes from cyclic voltammetry, which shows that the Pt core DENs catalyze the hydrogen evolution reaction before Cu UPD, but that after Cu UPD this reaction is inhibited. Results obtained by in situ electrochemical X-ray absorption spectroscopy (XAS) confirm this finding.

  18. Control of crystallite size in diamond film chemical vapor deposition

    Science.gov (United States)

    Moran, Mark B.; Johnson, Linda F.; Klemm, Karl A.

    1992-12-01

    In depositing an adhering, continuous, polycrystalline diamond film of optical or semiconductor quality on a substrate, as by forming on the substrate a layer of a refractory nitride interlayer and depositing diamond on the interlayer without mechanical treatment or seeding of the substrate or the interlayer, the substrate is heated in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon, and the size of deposited diamond crystallites and their rate of deposition selectively varied by a bias voltage applied to the substrate.

  19. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    OpenAIRE

    Zulkarnain Zainal; Mohd Norizam Md Daud; Azmi Zakaria; Mohd Sabri Mohd Ghazali; Atefeh Jafari; Wan Rafizah Wan Abdullah

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the ...

  20. Deposition of Cadmium Sulphide Thin Films by Photochemical Deposition and Characterization

    Directory of Open Access Journals (Sweden)

    H.L. Pushpalatha

    2015-03-01

    Full Text Available Deposition of cadmium sulphide (CdS thin films on glass substrates in acidic medium by photochemical deposition (PCD and studies by several characterizations are presented. The structural characterization of the thin films was carried out by XRD. The elemental composition of the thin films was carried out by EDAX. The optical properties have been studied in the wavelength range 200-900 nm and the optical transition has been found to be direct and allowed. The morphological properties are studied by AFM and electrical properties are studied by four probe technique.

  1. Properties of N-rich Silicon Nitride Film Deposited by Plasma-Enhanced Atomic Layer Deposition

    Science.gov (United States)

    Jhang, Pei-Ci; Lu, Chi-Pin; Shieh, Jung-Yu; Yang, Ling-Wu; Yang, Tahone; Chen, Kuang-Chao; Lu, Chih-Yuan

    2017-07-01

    An N-rich silicon nitride film, with a lower refractive index (RI) than the stoichiometric silicon nitride (RI = 2.01), was deposited by alternating the exposure of dichlorosilane (DCS, SiH2Cl2) and that of ammonia (NH3) in a plasma-enhanced atomic layer deposition (PEALD) process. In this process, the plasma ammonia was easily decomposed to reactive radicals by RF power activating so that the N-rich silicon nitride was easily formed by excited ammonia radicals. The growth kinetics of N-rich silicon nitride were examined at various deposition temperatures ranging from 400 °C to 630 °C; the activation energy (Ea) decreased as the deposition temperature decreased below 550 °C. N-rich silicon nitride film with a wide range of values of refractive index (RI) (RI = 1.86-2.00) was obtained by regulating the deposition temperature. At the optimal deposition temperature, the effects of RF power, NH3 flow rate and NH3 flow time were on the characteristics of the N-rich silicon nitride film were evaluated. The results thus reveal that the properties of the N-rich silicon nitride film that was formed by under plasma-enhanced atomic layer deposition (PEALD) are dominated by deposition temperature. In charge trap flash (CTF) study, an N-rich silicon nitride film was applied to MAONOS device as a charge-trapping layer. The films exhibit excellent electron trapping ability and favor a fresh cell data retention performance as the deposition temperature decreased.

  2. Thin film deposition of diamond using normal paraffins as source of diamond nucleation centers

    Energy Technology Data Exchange (ETDEWEB)

    Ershova, A., E-mail: ershovaangelina@mail.ru [Nano-Technology Laboratory, Triangle Inc., 01079 (Ukraine); Eizenbraun, A. [Nano-Technology Laboratory, Triangle Inc., 01079 (Ukraine)

    2012-11-15

    Highlights: ► Paraffin compounds are diamond nucleation sources. ► Thermoconductivity of Cu–DTF device is higher than such conductivity of Cu. ► DTF growth in HFCVD reactor is not linear function of time. -- Abstract: We propose a process for diamond thin film (DTF) deposition using normal paraffins (nP) as source of diamond nucleation centers. We deposited micro-crystalline diamond thin films (MCDTF) on a Cu substrate using Hot Filament CVD (HFCVD) and Passive Pt/Pd Surface Catalysis (PPt/PdSC) methods. Beeswax and a 1:1 mixture of normal paraffins of the general formula CH{sub 3}(CH{sub 2}){sub n}CH{sub 3} with n = 22 and 26 were tested as nP starting material. The films obtained were characterized by scanning electronic microscopy (SEM), Raman scattering temperature dependent spectroscopy and X-ray diffraction (XRD) methods, all of which confirmed that the deposited material is MCDTF.

  3. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    Directory of Open Access Journals (Sweden)

    John Meynard M. Tengco

    2016-06-01

    Full Text Available Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD and scanning transmission electron microscopy (STEM characterization of the base catalyst showed highly dispersed particles. A basic ED bath containing PtCl62− as the Pt precursor, dimethylamine borane as reducing agent, and ethylenediamine as stabilizing agent successfully targeted deposition of Pt on Co particles. Simultaneous action of galvanic displacement and ED resulted in Pt-Co alloy formation observed in XRD and energy dispersive X-ray spectroscopy (XEDS mapping. In addition, fast deposition kinetics resulted in hollow shell Pt-Co alloy particles while particles with Pt-rich shell and Co-rich cores formed with controlled Pt deposition. Electrochemical evaluation of the Pt-Co/C catalysts showed lower active surface but much higher mass and surface activities for oxygen reduction reaction compared to a commercial Pt/C fuel cell catalyst.

  4. Selected area chemical vapor deposition of thin films for conductometric microelectronic chemical sensors

    Science.gov (United States)

    Majoo, Sanjeev

    Recent advances in microelectronics and silicon processing have been exploited to fabricate miniaturized chemical sensors. Although the capability of chemical sensing technology has grown steadily, it has been outpaced by the increasing demands for more reliable, inexpensive, and selective sensors. The diversity of applications requires the deployment of different sensing materials that have rich interfacial chemistry. However, several promising sensor materials are often incompatible with silicon micromachining and their deposition requires complicated masking steps. The new approach described here is to first micromachine a generic, instrumented, conductometric, microelectronic sensor platform that is fully functional except for the front-end sensing element. This generic platform contains a thin dielectric membrane, an integrated boron-doped silicon heater, and conductance electrodes. The membrane has low thermal mass and excellent thermal isolation. A proprietary selected-area chemical vapor deposition (SACVD) process in a cold-wall reactor at low pressures was then used to achieve maskless, self-lithographic deposition of thin films. The temperature-programmable integrated microheater initiates localized thermal decomposition/reaction of suitable CVD precursors confined to a small heated area (500 mum in diameter), and this creates the active sensing element. Platinum and titania (TiOsb2) films were deposited from pyrolysis of organometallic precursors, tetrakistrifluorophosphine platinum Pt(PFsb3)sb4 and titanium tetraisopropoxide Ti(OCH(CHsb3)sb2rbrack sb4, respectively. Deposition of gold metal films from chlorotriethylphosphine gold (Csb2Hsb5)sb3PAuCl precursor was also attempted but without success. The conductance electrodes permit in situ monitoring of film growth. The as-deposited films were characterized in situ by conductance measurements and optical microscopy and ex situ by electron microscopy and spectroscopy methods. Devices equipped with

  5. Aspects of thin film deposition on granulates by physical vapor deposition

    Science.gov (United States)

    Eder, Andreas; Schmid, Gerwin H. S.; Mahr, Harald; Eisenmenger-Sittner, Christoph

    2016-11-01

    Thin film and coating technology has entered fields which may show significant deviations from classical coating applications where films are deposited on plane, sometimes large substrates. Often surfaces of small and irregularly shaped bodies have to be improved in respect to electrical, thermal or mechanical properties. Film deposition and characterization on such small substrates is not a trivial task. This specially holds for methods based on Physical Vapor Deposition (PVD) processes such as sputter deposition and its ion- and plasma assisted varieties. Due to their line of sight nature a key issue for homogenous films is efficient intermixing. If this problem is mastered, another task is the prediction and determination of the film thickness on single particles as well as on large scale ensembles thereof. In this work a mechanism capable of uniformly coating up to 1000 cm3 of granulate with particle sizes ranging from approx. 10 μm to 150 μm by magnetron sputtering is thoroughly described. A method for predicting the average film thickness on the particles is presented and tested for several differently shaped objects like microspheres, irregular grains of sinter powder or micro diamonds. For assessing the film thickness on single particles as well as on particle ensembles several complementary methods based on optics, X-ray analysis and gravimetry are employed. Their respective merits and limitations are discussed. Finally an outlook on adapting the described technology for surface modification by plasma based reactive and non-reactive processes is given.

  6. Deposition of Cu seed layer film by supercritical fluid deposition for advanced interconnects

    Institute of Scientific and Technical Information of China (English)

    Zhao Bin; Zhao Ming-Tao; Zhang Yan-Fei; Yang Jun-He

    2013-01-01

    The deposition of a Cu seed layer film is investigated by supercritical fluid deposition (SCFD) using H2 as a reducing agent for Bis(2,2,6,6-tetramethyl-3,5-heptanedionato) copper in supercritical CO2 (scCO2).The effects of deposition temperature,precursor,and H2 concentration are investigated to optimize Cu deposition.Continuous metallic Cu films are deposited on Ru substrates at 190 ℃ when a 0.002 mol/L Cu precursor is introduced with 0.75 mol/L H2.A Cu precursor concentration higher than 0.002 mol/L is found to have negative effects on the surface qualities of Cu films.For a H2concentration above 0.56 mol/L,the root-mean-square (RMS) roughness of a Cu film decreases as the H2 concentration increases.Finally,a 20-nm thick Cu film with a smooth surface,which is required as a seed layer in advanced interconnects,is successfully deposited at a high H2 concentration (0.75 mol/L).

  7. Plasma deposited fluorinated films on porous membranes

    Energy Technology Data Exchange (ETDEWEB)

    Gancarz, Irena [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Bryjak, Marek, E-mail: marek.bryjak@pwr.edu.pl [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Kujawski, Jan; Wolska, Joanna [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Kujawa, Joanna; Kujawski, Wojciech [Nicolaus Copernicus University, Faculty of Chemistry, 7 Gagarina St., 87-100 Torun (Poland)

    2015-02-01

    75 KHz plasma was used to modify track etched poly(ethylene terephthalate) membranes and deposit on them flouropolymers. Two fluorine bearing monomers were used: perflourohexane and hexafluorobenzene. The modified surfaces were analyzed by means of attenuated total reflection infra-red spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and wettability. It was detected that hexaflourobenxene deposited to the larger extent than perflourohaxane did. The roughness of surfaces decreased when more fluoropolymer was deposited. The hydrophobic character of surface slightly disappeared during 20-days storage of hexaflourobenzene modified membrane. Perfluorohexane modified membrane did not change its character within 120 days after modification. It was expected that this phenomenon resulted from post-reactions of oxygen with radicals in polymer deposits. The obtained membranes could be used for membrane distillation of juices. - Highlights: • Plasma deposited hydrophobic layer of flouropolymers. • Deposition degree affects the surface properties. • Hydrohilization of surface due to reaction of oxygen with entrapped radicals. • Possibility to use modified porous membrane for water distillation and apple juice concentration.

  8. Composition and size dependence of magnetic properties of FePt/Fe exchange-spring films

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yu; Zhang, Zhe; Duan, Nian; Wang, Jiawei; Chen, Yuang; Tong, Bei; Yang, Xiaofei; Zhang, Yue, E-mail: yue-zhang@mail.hust.edu.cn

    2014-12-15

    The composition and size dependence of the magnetic properties of FePt/Fe exchange-spring bilayer films was studied using micromagnetic simulation. Based on the simulated hysteresis loops for composite layers with an identical thickness of 20 nm and different composition ratios, it can be observed that when the thickness ratio of Fe is 10%, an exchange-spring effect with a negative nucleation field appears; the switching field is greatly reduced compared to the rigid magnetic FePt, and the squareness ratio reaches its maximum value. When the thickness ratio of Fe is 25% and more, the nucleation fields become positive; meanwhile, the coercivity is smaller than the switching field, and the squareness ratio decreases because of the increase in the thickness of the Fe film. In addition, at a fixed thickness ratio and total volume, the switching field of the FePt/Fe bilayer films is further reduced, accompanied by a decrease in the squareness ratio due to an increase in the thickness of the Fe layer. - Highlights: • Exchange-spring behavior of FePt/Fe multi-layers was studied via micro-magnetic simulation. • As total thickness is 20 nm, optimal magnetic property is shown when the thickness ratio of Fe is 10%. • As total thickness is 20 nm, nucleation fields are positive when the thickness ratio of Fe is 25% and larger. • As total thickness is 20 nm, coercivity is greatly reduced when the thickness ratio of Fe is 25% and larger. • Under fixed volume and the thickness ratio of Fe (10%), switching field can be reduced by reducing the bottom size.

  9. Ultraviolet laser deposition of graphene thin films without catalytic layers

    KAUST Repository

    Sarath Kumar, S. R.

    2013-01-09

    In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

  10. Shallow bath chemical deposition of CdS thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Y.S. [Department of Molecule Science and Engineering, National Taipei University of Science and Technology, Taipei, 10617, Taiwan (China); Choubey, R.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi, 835 215 (India); Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan (China); Yu, W.C. [Department of Molecule Science and Engineering, National Taipei University of Science and Technology, Taipei, 10617, Taiwan (China); Hsu, W.T. [Green Energy and Environmental Research Laboratory, Industrial Technology Research Institute, Hsin-Chu, Taiwan (China); Lan, C.W., E-mail: cwlan@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan (China)

    2011-10-31

    Cadmium sulfide thin film was grown by shallow chemical bath deposition technique. This technique used a highly conducted hot plate to heat the substrate, while using a shallow bath for higher thermal gradients. As a result, large area uniformity could be achieved and the homogeneous nucleation was suppressed. More importantly, the solution used was greatly reduced, which is crucial for cost reduction in practice. The effects of temperature and shaking on the growth kinetics and film properties were investigated. The reaction activation energy was obtained to be 0.84 eV, and was not affected much by shaking indicating that the deposition is essentially reaction controlled. Furthermore, the films deposited at low or high temperature conditions had better photoconductivity.

  11. Investigation of fabrication and hetero-epitaxy relationship of CoCrPt thin films grown on CrW underlayer

    Institute of Scientific and Technical Information of China (English)

    Li Song-Tian; Liu Xi; Shi Wen-Kui; Cao Jiang-Wei; Wei Fu-Lin; Wei Dan

    2009-01-01

    This paper reports that longitudinally oriented CoCrPt thin films with Cr85W15 underlayer and CoCr intermediate layer for use of giant magnetoresistance heads were fabricated by magnetron sputtering.Without CoCr intermediate layer,CoCrPt layer deposited directly on Cr85W15 underlayer which has a dominant(200)texture exhibits unexpected(10-11)texture.After introducing CoCr intermediate layer,the CoCrPt layer shifts into(1120)texture.This article studies the crystallographic hetero-epitaxy relationship between magnetic layer and underlayer in order to understand the appearance of CoCrPt(10-11)texture on(200)textured Cr underlayer and the influence of CoCr intermediate layer on the inducement of CoCrPt(11-20)texture.The CoCr intermediate layer plays a crucial role in controlling the microstructure and consequently the magnetic properties of the overlying magnetic layer.

  12. Cobalt Xanthate Thin Film with Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    İ. A. Kariper

    2013-01-01

    Full Text Available Cobalt xanthate thin films (CXTFs were successfully deposited by chemical bath deposition, onto amorphous glass substrates, as well as on p- and n-silicon, indium tin oxide, and poly(methyl methacrylate. The structure of the films was analyzed by far-infrared spectrum (FIR, mid-infrared (MIR spectrum, nuclear magnetic resonance (NMR, and scanning electron microscopy (SEM. These films were investigated from their structural, optical, and electrical properties point of view. Electrical properties were measured using four-point method, whereas optical properties were investigated via UV-VIS spectroscopic technique. Uniform distribution of grains was clearly observed from the photographs taken by scanning electron microscope (SEM. The transmittance was about 70–80% (4 hours, 50°C. The optical band gap of the CXTF was graphically estimated to be 3.99–4.02 eV. The resistivity of the films was calculated as 22.47–75.91 Ω·cm on commercial glass depending on film thickness and 44.90–73.10 Ω ·cm on the other substrates. It has been observed that the relative resistivity changed with film thickness. The MIR and FIR spectra of the films were in agreement with the literature analogues. The expected peaks of cobalt xanthate were observed in NMR analysis on glass. The films were dipped in chloroform as organic solvent and were analyzed by NMR.

  13. Electron-beam deposition of vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Marvel, R.E.; Appavoo, K. [Vanderbilt University, Interdisciplinary Materials Science Program, Nashville, TN (United States); Choi, B.K. [Vanderbilt University, Department of Electrical Engineering and Computer Science, Nashville, TN (United States); Nag, J. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Haglund, R.F. [Vanderbilt University, Interdisciplinary Materials Science Program, Nashville, TN (United States); Vanderbilt University, Institute for Nanoscale Science and Engineering, Nashville, TN (United States); Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States)

    2013-06-15

    Developing a reliable and efficient fabrication method for phase-transition thin-film technology is critical for electronic and photonic applications. We demonstrate a novel method for fabricating polycrystalline, switchable vanadium dioxide thin films on glass and silicon substrates and show that the optical switching contrast is not strongly affected by post-processing annealing times. The method relies on electron-beam evaporation of a nominally stoichiometric powder, followed by fast annealing. As a result of the short annealing procedure we demonstrate that films deposited on silicon substrates appear to be smoother, in comparison to pulsed laser deposition and sputtering. However, optical performance of e-beam evaporated film on silicon is affected by annealing time, in contrast to glass. (orig.)

  14. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres.

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-04-21

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m(-1). During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □(-1) with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H₂O₂ electrode with a sensitivity of 0.56 mA mM(-1) cm(-2), a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM(-1) cm(-2) and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.

  15. Microwave annealing effects on ZnO films deposited by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    Zhao Shirui; Dong Yabin; Yu Mingyan; Guo Xiaolong; Xu Xinwei; Jing Yupeng; Xia Yang

    2014-01-01

    Zinc oxide thin films deposited on glass substrate at 150 ℃ by atomic layer deposition were annealed by the microwave method at temperatures below 500 ℃.The microwave annealing effects on the structural and luminescent properties of ZnO films have been investigated by X-ray diffraction and photoluminescence.The results show that the MWA process can increase the crystal quality of ZnO thin films with a lower annealing temperature than RTA and relatively decrease the green luminescence of ZnO films.The observed changes have demonstrated that MWA is a viable technique for improving the crystalline quality of ZnO thin film on glass.

  16. Characterization of Thin Films Deposited with Precursor Ferrocene by Plasma Enhanced Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    YAO Kailun; ZHENG Jianwan; LIU Zuli; JIA Lihui

    2007-01-01

    In this paper,the characterization of thin films,deposited with the precursor ferrocene(FcH)by the plasma enhanced chemical vapour deposition(PECVD)technique,was investigated.The films were measured by Scanning Electronic Microscopy(SEM),Atomic Force Microscopy(AFM),Electron Spectroscopy for Chemical Analysis(ESCA),and superconducting Quantum Interference Device(SQUID).It was observed that the film's layer is homogeneous in thickness and has a dense morphology without cracks.The surface roughness is about 36 nm.From the results of ESCA,it can be inferred that the film mainly contains the compound FeOOH,and carbon is combined with oxygen in different forms under different supply-powers.The hysteresis loops indicate that the film is of soft magnetism.

  17. Influence of multiple reflection and optical interference on the magneto-optical properties of Co-Pt alloy films investigated by using the characteristic matrix method

    CERN Document Server

    Zou, Z Q; Kim, K W

    2000-01-01

    The magneto-optical Kerr effect (MOKE) of a multilayered system was described by using the characteristic matrix method based on the electromagnetic wave theory. In addition to the multiple reflection and the optical interference, a contribution from the plasma resonance absorption of a metallic layer can be included in the formulation. As an example, we carried out a simulation of the MOKE for Co sub 0 sub . sub 2 sub 5 Pt sub 0 sub . sub 7 sub 5 alloy films with and without a Pt buffer layer. It was found that the Kerr rotation and the read-out figure of merit of a film directly deposited on a glass substrate were enhanced at a thickness below 40 nm owing to the multiple reflection and the optical interference. This enhancement was more remakable at long wavelengths when light was incident on the substrate side. However, the introduction of a Pt buffer layer was not beneficial in improving the Kerr rotation and the figure of merit, although it promoted the perpendicular magnetic anisotropy of the film, as r...

  18. Stress control of silicon nitride films deposited by plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Li, Dong-ling; Feng, Xiao-fei; Wen, Zhi-yu; Shang, Zheng-guo; She, Yin

    2016-07-01

    Stress controllable silicon nitride (SiNx) films deposited by plasma enhanced chemical vapor deposition (PECVD) are reported. Low stress SiNx films were deposited in both high frequency (HF) mode and dual frequency (HF/LF) mode. By optimizing process parameters, stress free (-0.27 MPa) SiNx films were obtained with the deposition rate of 45.5 nm/min and the refractive index of 2.06. Furthermore, at HF/LF mode, the stress is significantly influenced by LF ratio and LF power, and can be controlled to be 10 MPa with the LF ratio of 17% and LF power of 150 W. However, LF power has a little effect on the deposition rate due to the interaction between HF power and LF power. The deposited SiNx films have good mechanical and optical properties, low deposition temperature and controllable stress, and can be widely used in integrated circuit (IC), micro-electro-mechanical systems (MEMS) and bio-MEMS.

  19. Glancing angle deposition of thin films engineering the nanoscale

    CERN Document Server

    Hawkeye, Matthew M; Brett, Michael J

    2014-01-01

    This book provides a highly practical treatment of GLAD technology, gathering existing procedures, methodologies, and experimental designs into a single, cohesive volume which will be useful both as a ready reference for those in the field and as a definitive guide for those entering it. It covers: History and development of GLAD techniquesProperties and Characterization of GLAD fabricated filmsDesign and engineering of optical GLAD films including fabrication and testingPost-deposition processing and integrationDeposition systems for GLAD fabrication Also includes a patent survey of relevant literature and a survey of GLAD's wide range of material properties and diverse applications.

  20. Spray pyrolysis deposition of indium sulphide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Otto, K.; Katerski, A.; Mere, A.; Volobujeva, O.; Krunks, M., E-mail: malle@staff.ttu.e

    2011-03-01

    In{sub 2}S{sub 3} thin films were grown by the chemical spray pyrolysis (CSP) method using the pneumatic spray set-up and compressed air as a carrier gas. Aqueous solutions containing InCl{sub 3} and SC(NH{sub 2}){sub 2} at a molar ratio of In/S = 1/3 and 1/6 were deposited onto preheated glass sheets at substrate temperatures T{sub s} = 205-410 {sup o}C. The obtained films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM,) optical transmission spectra, X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). According to XRD, thin films deposited at T{sub s} = 205-365 {sup o}C were composed of the (0 0 12) orientated tetragonal {beta}-In{sub 2}S{sub 3} phase independent of the In/S ratio in the spray solution. Depositions performed at T{sub s} = 410 {sup o}C led to the formation of the In{sub 2}O{sub 3} phase, preferably when the 1/3 solution was sprayed. Post-deposition annealing in air indicated that oxidation of the sulphide phase has a minor role in the formation of In{sub 2}O{sub 3} at temperatures up to 450 {sup o}C. In{sub 2}S{sub 3} films grown at T{sub s} below 365 {sup o}C exhibited transparency over 70% in the visible spectral region and E{sub g} of 2.90-2.96 eV for direct and 2.15-2.30 eV for indirect transitions, respectively. Film thickness and chlorine content decreased with increasing deposition temperatures. The XPS study revealed that the In/S ratio in the spray solution had a significant influence on the content of oxygen (Me-O, BE = 530.0 eV) in the In{sub 2}S{sub 3} films deposited in the temperature range of 205-365 {sup o}C. Both XPS and EDS studies confirmed that oxygen content in the films deposited using the solution with the In/S ratio of 1/6 was substantially lower than in the films deposited with the In/S ratio of 1/3.

  1. Alternating current characterization of nano-Pt(II) octaethylporphyrin (PtOEP) thin film as a new organic semiconductor

    Science.gov (United States)

    M, Dongol; M, M. El-Nahass; A, El-Denglawey; A, A. Abuelwafa; T, Soga

    2016-06-01

    Alternating current (AC) conductivity and dielectric properties of thermally evaporated Au/PtOEP/Au thin films are investigated each as a function of temperature (303 K-473 K) and frequency (50 Hz-5 MHz). The frequency dependence of AC conductivity follows the Jonscher universal dynamic law. The AC-activation energies are determined at different frequencies. It is found that the correlated barrier hopping (CBH) model is the dominant conduction mechanism. The variation of the frequency exponent s with temperature is analyzed in terms of the CBH model. Coulombic barrier height W m , hopping distance R ω , and the density of localized states N(E F) are valued at different frequencies. Dielectric constant ɛ 1(ω,T) and dielectric loss ɛ 2(ω,T) are discussed in terms of the dielectric polarization process. The dielectric modulus shows the non-Debye relaxation in the material. The extracted relaxation time by using the imaginary part of modulus (M″) is found to follow the Arrhenius law.

  2. Abnormal infrared effects of nanometer scale thin film material of PtPd alloy in CO adsorption

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanometer scale thin film material of PtPd alloy supported on glassy carbon (nm-PtPd/GC) was prepared by the electrochemical codeposition method under cyclic voltammetric conditions. STM patterns demonstrated that the prepared thin films are composed of layered crystallites in elliptic form. Electrochemical in situ FTIRS studies explored the abnormal infrared effects (AIREs) of nmPtPd/GC for CO adsorption, which are ( i ) the remarkable enhancement of IR absorption, (ii) the inversion of COad band direction, and (iii) notable increase in the full width at half maximum (FWHM) of COad bands. The results demonstrated also that the enhancement factor of IR absorption varies with the thickness of PtPd alloy film and has reached a maximum value of 38.3 under the experimental conditions.

  3. First principles investigation of the activity of thin film Pt, Pd and Au surface alloys for oxygen reduction

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Hansen, Heine Anton; Rossmeisl, Jan

    2015-01-01

    Further advances in fuel cell technologies are hampered by kinetic limitations associated with the sluggish cathodic oxygen reduction reaction. We have investigated a range of different formulations of binary and ternary Pt, Pd and Au thin films as electrocatalysts for oxygen reduction. The most...... active binary thin films are near-surface alloys of Pt with subsurface Pd and certain PdAu and PtAu thin films with surface and/or subsurface Au. The most active ternary thin films are with pure metal Pt or Pd skins with some degree of Au in the surface and/or subsurface layer and the near-surface alloys....... This is particularly challenging for alloys containing Au due to a high propensity of Au to segregate to the surface. We also show that once Au is on the surface it will diffuse to defect sites, explaining why small amounts of Au retard dissolution of Pt nanoparticles. For the PtPd thin films there is no pronounced...

  4. Study of indium tin oxide thin films deposited on acrylics substrates by Ion beam assisted deposition technique

    OpenAIRE

    Meng Lijian; Liang Erjun; Gao Jinsong; Teixeira, Vasco M. P.; Santos, M. P. dos

    2009-01-01

    Indium tin oxide (ITO) thin films have been deposited onto acrylics (PMMA) substrates by ion beam assisted deposition technique at different oxygen flows. The structural, optical and electrical properties of the deposited films have been characterized by X-ray diffraction, transmittance, FTIR, ellipometry and Hall effect measurements. The optical constants of the deposited films have been calculated by fitting the ellipsometric spectra. The effects of the oxygen flow on the properties of the ...

  5. Fabrication and characterization of vacuum deposited fluorescein thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, Pasi, E-mail: pasi.jalkanen@gmail.co [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Kulju, Sampo, E-mail: sampo.j.kulju@jyu.f [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Arutyunov, Konstantin, E-mail: konstantin.arutyunov@jyu.f [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Antila, Liisa, E-mail: liisa.j.antila@jyu.f [University of Jyvaeskylae, Department of Chemistry, Nanoscience center (NSC) P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Myllyperkioe, Pasi, E-mail: pasi.myllyperkio@jyu.f [University of Jyvaeskylae, Department of Chemistry, Nanoscience center (NSC) P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Ihalainen, Teemu, E-mail: teemu.o.ihalainen@jyu.f [University of Jyvaeskylae, Department of Biology, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Kaeaeriaeinen, Tommi, E-mail: tommi.kaariainen@lut.f [Lappeenranta University of Technology, ASTRal, P.O. Box 181, FI-50101 Mikkeli (Finland); Kaeaeriaeinen, Marja-Leena, E-mail: marja-leena.kaariainen@lut.f [Lappeenranta University of Technology, ASTRal, P.O. Box 181, FI-50101 Mikkeli (Finland); Korppi-Tommola, Jouko, E-mail: jouko.korppi-tommola@jyu.f [University of Jyvaeskylae, Department of Biology, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland)

    2011-03-31

    Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO{sub 2} coating. Surface topology, absorption and emission spectra of the films depend on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially forms islands before merging into a uniform layer after 5 to 10 monolayers. On FTO covered glass the absorption spectra are similar to fluorescein solution in ethanol. Absorption spectra on ALD-TiO{sub 2} is red shifted compared to the film deposited on bare FTO. The corresponding emission spectra at {lambda} = 458 nm excitation show various thickness and substrate dependent features, while the emission of films deposited on TiO{sub 2} is quenched due to the effective electron transfer to the semiconductor conduction band.

  6. Electric field-controlled magnetization switching in Co/Pt thin-film ferromagnets

    Directory of Open Access Journals (Sweden)

    A. Siddique

    2016-12-01

    Full Text Available A study of dynamic and reversible voltage-controlled magnetization switching in ferromagnetic Co/Pt thin film with perpendicular magnetic anisotropy at room temperature is presented. The change in the magnetic properties of the system is observed in a relatively thick film of 15 nm. A surface charge is induced by the formation of electrochemical double layer between the metallic thin film and non-aqueous lithium LiClO4 electrolyte to manipulate the magnetism. The change in the magnetic properties occurred by the application of an external electric field. As the negative voltage was increased, the coercivity and the switching magnetic field decreased thus activating magnetization switching. The results are envisaged to lead to faster and ultra-low-power magnetization switching as compared to spin-transfer torque (STT switching in spintronic devices.

  7. Tip-Dependent Scanning Tunneling Microscopy Imaging of Ultrathin FeO Films on Pt(111)

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Grabow, Lars C.; Peng, Guowen

    2011-01-01

    High-resolution scanning tunneling microscope (STM) images of moiré-structured FeO films on Pt(111) were obtained in a number of different tip-dependent imaging modes. For the first time, the STM images are distinguished and interpreted unambiguously with the help of distinct oxygen-vacancy dislo......High-resolution scanning tunneling microscope (STM) images of moiré-structured FeO films on Pt(111) were obtained in a number of different tip-dependent imaging modes. For the first time, the STM images are distinguished and interpreted unambiguously with the help of distinct oxygen......-vacancy dislocation loops in the FeO moiré structure. The experimental STM results are compared with the results of electronic structure calculations within the DFT+U scheme for a realistic (sqrt(91)xsqrt(91)R5.2 moiré unit cell supported on Pt(111) as well as with the results from previous studies. We find that one...... on the specific tip apex state and likely result from specific tip-sample chemical interactions. From the present STM results we show that several of the previously published conclusions for the FeO system have to be revisited....

  8. Electrochromic and electrochemical capacitive properties of tungsten oxide and its polyaniline nanocomposite films obtained by chemical bath deposition method

    CSIR Research Space (South Africa)

    Nwanya, AC

    2014-05-01

    Full Text Available Kenneth I. Ozoemena Fabian I. EzemaISE student member.ISE member. PII: S0013...-mail address: fiezema@yahoo.com 1 ISE student member 2 ISE member Page 2 of 31 Ac ce pte d M an us cri pt 2 Polyanine and its nanocomposite WO3/PANI films were deposited on Fluorine doped tin oxide (FTO) glass slides by simple Chemical Bath Deposition Method...

  9. Temperature dependence of spin Hall magnetoresistance in thin YIG/Pt films

    Science.gov (United States)

    Marmion, S. R.; Ali, M.; McLaren, M.; Williams, D. A.; Hickey, B. J.

    2014-06-01

    We report on the temperature dependence of the recently discovered spin Hall magnetoresistance in a yttrium iron garnet (YIG)/platinum (Pt) thin film. The YIG/Pt layers are an ideal choice as the combination of an insulating magnetic material and the high spin-orbit interaction in Pt gives a relatively large magnetoresistance and no electrical conduction occurs in the YIG. The temperature dependence of the magnetoresistance was measured between 1.4 K and 280 K from which the temperature dependence of the spin diffusion length in Pt has been extracted. We found that the best agreement between our data and the recently published [Chen et al., Phys. Rev. B 87, 144411 (2013), 10.1103/PhysRevB.87.144411] theory of the spin Hall magnetoresistance is given by an assumed Elliot-Yafet mechanism of spin relaxation with temperature-independent spin Hall angle and spin mixing conductance. The best estimate for the spin diffusion length returns values between 0.57 and 3.85 nm.

  10. Chemical Vapour Deposition of Graphene with Re-useable Pt and Cu substrates for Flexible Electronics

    Science.gov (United States)

    Karamat, Shumaila; Sonusen, Selda; Celik, Umit; Uysalli, Yigit; Oral, Ahmet

    2015-03-01

    Graphene has gained the attention of scientific world due to its outstanding physical properties. The future demand of flexible electronics such as solar cells, light emitting diodes, photo-detectors and touch screen technology requires more exploration of graphene properties on flexible substrates. The most interesting application of graphene is in organic light emitting diodes (OLED) where efforts are in progress to replace brittle indium tin oxide (ITO) electrode with a flexible graphene electrode because ITO raw materials are becoming increasingly expensive, and its brittle nature makes it unsuitable for flexible devices. In this work, we grow graphene on Pt and Cu substrates using chemical vapour deposition (CVD) and transferred it to a polymer material (PVA) using lamination technique. We used hydrogen bubbling method for separating graphene from Pt and Cu catalyst to reuse the substrates many times. After successful transfer of graphene on polymer samples, we checked the resistivity values of the graphene sheet which varies with growth conditions. Furthermore, Raman, atomic force microscopy (AFM), I-V and Force-displacement measurements will be presented for these samples.

  11. Perpendicular magnetic anisotropy of FePt film on Si substrate with SiO{sub 2} underlayer and B{sub 4}C interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)], E-mail: nanoguy@126.com; Yang, F.J. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)], E-mail: yangfujun77@sina.com; Mo, Q.; Zhang, J.; Wang, H.B.; Wang, Y. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)

    2009-09-15

    FePt multilayer composite films with and without B{sub 4}C interlayer have been prepared by magnetron sputtering, respectively, and subsequent annealing in vacuum. It was found that the B{sub 4}C layers effectively serve as spacers to separate the FePt layers, enhancing (0 0 1) orientation of FePt alloy. Our results show that highly (0 0 1) oriented FePt/B{sub 4}C films have significant potential as perpendicular recording media.

  12. The Effect of Deposition Time on Textured Magnesium Diboride Thick Films Fabricated by Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    W. G. Mutia

    2004-12-01

    Full Text Available MgB2 powders suspended in ethanol were electrophoretically deposited on high-purity molybdenum substrates having dimensions of 1 x 0.3 x 0.01 cm. The said substrate was set as the cathode and was placed 0.5 cm away from a graphite rod anode. A current density of ~0.02 mA/cm2 and a voltage of 600 V were applied. The effect of deposition time was studied by varying it as follows: 15 s, 30 s, 1 min, and 2 min. Heat treatment at 950 oC for 3 h was done after deposition. MgB2 thick films were successfully fabricated for the deposition carried out for 2 min. Deposition times less than 2 min resulted in insufficient deposited powder; hence formation of MgB2 was not facilitated. Films deposited at 15 and 30 s have good surface characteristics, wherein no microcracks were present. X-ray diffraction and surface image analysis reveal that the deposited films have a preferred orientation along the (10l direction.

  13. Morphological Study Of Palladium Thin Films Deposited By Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, K L; Rodriguez, C A [Grupo Plasma Laser y Aplicaciones, Ingenieria Fisica, Universidad Tecnologica de Pereira (Colombia); Perez, F A [WNANO, West Virginia University (United States); Riascos, H [Grupo Plasma Laser y Aplicaciones, Departamento de Fisica, Universidad Tecnologica de Pereira (Colombia)

    2011-01-01

    This paper presents a morphological analysis of thin films of palladium (Pd) deposited on a substrate of sapphire (Al{sub 2}O{sub 3}) at a constant pressure of 3.5 mbar at different substrate temperatures (473 K, 523 K and 573 K). The films were morphologically characterized by means of an Atomic Force Microscopy (AFM); finding a relation between the roughness and the temperature. A morphological analysis of the samples through AFM was carried out and the roughness was measured by simulating the X-ray reflectivity curve using GenX software. A direct relation between the experimental and simulation data of the Palladium thin films was found.

  14. Alternating deposition films of a polymer and dendrimers bearing diphenylanthracene

    Institute of Scientific and Technical Information of China (English)

    SUN Jing; WANG Liyan; GAO Jian; YU Xi; WANG Zhiqiang

    2005-01-01

    Two generations of carboxyl-terminated poly (aryl ether) dendrimers bearing 9,10-diphenylanthracene cores are designed and synthesized. Alternating deposition of two dendrimers and poly(4-vinylpyridine) is studied with UV-Vis spectroscopy, FT-IR spectroscopy and atomic force microscopy. Experimental results indicate that this method to introduce chromophore into multilayer film can effectively prevent desorption of dye molecule. Moreover, it is found that dendrimer can inhibit the aggregation of fluorophore in film using fluorescence spectroscopy. Increase of dendrimer's generation can enhance fluorescence intensity of each fluorophore. This provides a new approach to design luminescent thin film.

  15. Impact toughness of tungsten films deposited on martensite stainless steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Ning-kang; YANG Bin; WANG De-zhi

    2005-01-01

    Tungsten films were deposited on stainless steel Charpy specimens by magnetron sputtering followed by electron beam heat treatment. Charpy impact tests and scanning electron microscopy were used to investigate the ductile-brittle transition behavior of the specimens. With decreasing test temperature the fracture mode was transformed from ductile to brittle for both kinds of specimens with and without W films. The data of the crack initiation energy, crack propagation energy, impact absorbing energy, fracture time and deflection as well as the fracture morphologies at test temperature of -70 ℃ show that W films can improve the impact toughness of stainless steel.

  16. Oxide films: low-temperature deposition and crystallization

    Science.gov (United States)

    Park, Sangmoon; Herman, Gregory S.; Keszler, Douglas A.

    2003-10-01

    Thin films of CeO 2 and (Ce,Sm)O 2 have been prepared by using the SILAR method of deposition in conjunction with hydrothermal and high-temperature annealing. Low-temperature, low-pressure hydrothermal annealing of amorphous Mn:Zn 2GeO 4 films has lead to the growth of grains having edge lengths near 1 μm. Thick films of crystalline Zn 2SiO 4 exhibiting limited cracking have been prepared by a doctor-blade method also in conjunction with hydrothermal dehydration and annealing.

  17. Absence of morphotropic phase boundary effects in BiFeO3-PbTiO3 thin films grown via a chemical multilayer deposition method

    Science.gov (United States)

    Gupta, Shashaank; Bhattacharjee, Shuvrajyoti; Pandey, Dhananjai; Bansal, Vipul; Bhargava, Suresh K.; Peng, Ju Lin; Garg, Ashish

    2011-07-01

    We report an unusual behavior observed in (BiFeO3)1- x -(PbTiO3) x (BF- xPT) thin films prepared using a multilayer chemical solution deposition method. Films of different compositions were grown by depositing several bilayers of BF and PT precursors of varying BF and PT layer thicknesses followed by heat treatment in air. X-ray diffraction showed that samples of all compositions show mixing of two compounds resulting in a single-phase mixture, also confirmed by transmission electron microscopy. In contrast to bulk compositions, samples show a monoclinic (MA-type) structure suggesting disappearance of the morphotropic phase boundary (MPB) at x=0.30 as observed in the bulk. This is accompanied by the lack of any enhancement of the remanent polarization at the MPB, as shown by the ferroelectric measurements. Magnetic measurements showed an increase in the magnetization of the samples with increasing BF content. Significant magnetization in the samples indicates melting of spin spirals in the BF- xPT films, arising from a random distribution of iron atoms. Absence of Fe2+ ions was corroborated by X-ray photoelectron spectroscopy measurements. The results illustrate that thin film processing methodology significantly changes the structural evolution, in contrast to predictions from the equilibrium phase diagram, besides modifying the functional characteristics of the BP- xPT system dramatically.

  18. A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation

    Science.gov (United States)

    Roller, Justin M.; Maric, Radenka

    2015-12-01

    Catalytic materials are complex systems in which achieving the desired properties (i.e., activity, selectivity and stability) depends on exploiting the many degrees of freedom in surface and bulk composition, geometry, and defects. Flame aerosol synthesis is a process for producing nanoparticles with ample processing parameter space to tune the desired properties. Flame dynamics inside the reactor are determined by the input process variables such as solubility of precursor in the fuel; solvent boiling point; reactant flow rate and concentration; flow rates of air, fuel and the carrier gas; and the burner geometry. In this study, the processing parameters for reactive spray deposition technology, a flame-based synthesis method, are systematically evaluated to understand the residence times, reactant mixing, and temperature profiles of flames used in the synthesis of Pt nanoparticles. This provides a framework for further study and modeling. The flame temperature and length are also studied as a function of O2 and fuel flow rates.

  19. Deposition of ZnO Films on Freestanding CVD Thick Diamond Films

    Institute of Scientific and Technical Information of China (English)

    SUN Jian; BAI Yi-Zhen; YANG Tian-Peng; XU Yi-Bin; WANG Xin-Sheng; DU Guo-Tong; WU Han-Hua

    2006-01-01

    @@ For ZnO/diamond structured surface acoustic wave (SAW) filters, performance is sensitively dependent on the quality of the ZnO films. In this paper, we prepare highly-oriented and fine grained polycrystalline ZnO thin films with excellent surface smoothness on the smooth nucleation surfaces of freestanding CVD diamond films by metal organic chemical vapour deposition (MOCVD). The properties of the ZnO films are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectrum. The influences of the deposition conditions on the quality of ZnO films are discussed briefly. ZnO/freestanding thick-diamond-film layered SAW devices with high response frequencies are expected to be developed.

  20. Cadmium Sulfide Thin Films Deposited onto MWCNT/Polysulfone Substrates by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    M. Moreno

    2016-01-01

    Full Text Available Cadmium sulfide (CdS thin films were deposited by chemical bath deposition (CBD onto polymeric composites with electric field-aligned multiwall carbon nanotubes (MWCNTs. MWCNT/polysulfone composites were prepared by dispersing low concentrations of MWCNTs within dissolved polysulfone (PSF. An alternating current electric field was “in situ” applied to align the MWCNTs within the dissolved polymer along the field direction until the solvent was evaporated. 80 μm thick solid MWCNT/PSF composites with an electrical conductivity 13 orders of magnitude higher than the conductivity of the neat PSF were obtained. The MWCNT/PSF composites were subsequently used as flexible substrates for the deposition of CdS thin films by CBD. Transparent and adherent CdS thin films with an average thickness of 475 nm were obtained. The values of the energy band gap, average grain size, rms roughness, crystalline structure, and preferential orientation of the CdS films deposited onto the polymeric substrate were very similar to the corresponding values of the CdS deposited onto glass (conventional substrate. These results show that the MWCNT/PSF composites with electric field-tailored MWCNTs represent a suitable option to be used as flexible conducting substrate for CdS thin films, which represents an important step towards the developing of flexible systems for photovoltaic applications.

  1. Coaxial carbon plasma gun deposition of amorphous carbon films

    Science.gov (United States)

    Sater, D. M.; Gulino, D. A.; Rutledge, S. K.

    1984-01-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented.

  2. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José

    2010-10-24

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

  3. Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films.

    Science.gov (United States)

    Haile, Merid; Sarwar, Owais; Henderson, Robert; Smith, Ryan; Grunlan, Jaime C

    2017-01-01

    Multilayer coatings consisting of oppositely charged polyelectrolytes have proven to be extraordinarily effective oxygen barriers but require many processing steps to fabricate. In an effort to prepare high oxygen barrier thin films more quickly, a polyelectrolyte complex coacervate composed of polyethylenimine and polyacrylic acid is prepared. The coacervate fluid is applied as a thin film using a rod coating process. With humidity and thermal post-treatment, a 2 µm thin film reduces the oxygen transmission rate of 0.127 mm poly(ethylene terephthalate) by two orders of magnitude, rivalling conventional oxygen barrier technologies. These films are fabricated in ambient conditions using low-cost, water-based solutions, providing a tremendous opportunity for single-step deposition of polymeric high barrier thin films.

  4. CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER COATING LAYER FOR POLYMER FILM

    Institute of Scientific and Technical Information of China (English)

    Xiao-ning Liu; Gi Xue; Yun Lu; Jun Zhang; Fen-ting Li; Chen-chen Xue; Stephen Z.D. Cheng

    2001-01-01

    When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surfaceenhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

  5. Giant perpendicular magnetic anisotropy energies in CoPt thin films: impact of reduced dimensionality and imperfections.

    Science.gov (United States)

    Brahimi, Samy; Bouzar, Hamid; Lounis, Samir

    2016-12-14

    The impact of reduced dimensionality on the magnetic properties of the tetragonal L1 0 CoPt alloy is investigated from ab initio considering several kinds of surface defects. By exploring the dependence of the magnetocrystalline anisotropy energy (MAE) on the thickness of CoPt thin films, we demonstrate the crucial role of the chemical nature of the surface. For instance, Pt-terminated thin films exhibit huge MAEs which can be 1000% larger than those of Co-terminated films. Besides the perfect thin films, we scrutinize the effect of defective surfaces such as stacking faults or anti-sites on the surface layers. Both types of defects reduce considerably the MAE with respect to the one obtained for Pt-terminated thin films. A detailed analysis of the electronic structure of the thin films is provided with a careful comparison to the CoPt bulk case. The behavior of the MAEs is then related to the location of the different virtual bound states utilizing second order perturbation theory.

  6. Giant perpendicular magnetic anisotropy energies in CoPt thin films: impact of reduced dimensionality and imperfections

    Science.gov (United States)

    Brahimi, Samy; Bouzar, Hamid; Lounis, Samir

    2016-12-01

    The impact of reduced dimensionality on the magnetic properties of the tetragonal L1 0 CoPt alloy is investigated from ab initio considering several kinds of surface defects. By exploring the dependence of the magnetocrystalline anisotropy energy (MAE) on the thickness of CoPt thin films, we demonstrate the crucial role of the chemical nature of the surface. For instance, Pt-terminated thin films exhibit huge MAEs which can be 1000% larger than those of Co-terminated films. Besides the perfect thin films, we scrutinize the effect of defective surfaces such as stacking faults or anti-sites on the surface layers. Both types of defects reduce considerably the MAE with respect to the one obtained for Pt-terminated thin films. A detailed analysis of the electronic structure of the thin films is provided with a careful comparison to the CoPt bulk case. The behavior of the MAEs is then related to the location of the different virtual bound states utilizing second order perturbation theory.

  7. Fabrication of single TiO2 nanotube devices with Pt interconnections using electron- and ion-beam-assisted deposition

    Science.gov (United States)

    Lee, Mingun; Cha, Dongkyu; Huang, Jie; Ha, Min-Woo; Kim, Jiyoung

    2016-06-01

    Device fabrication using nanostructured materials, such as nanotubes, requires appropriate metal interconnections between nanotubes and electrical probing pads. Here, electron-beam-assisted deposition (EBAD) and ion-beam-assisted deposition (IBAD) techniques for fabrication of Pt interconnections for single TiO2 nanotube devices are investigated. IBAD conditions were optimized to reduce the leakage current as a result of Pt spreading. The resistivity of the IBAD-Pt was about three orders of magnitude less than that of the EBAD-Pt, due to low carbon concentration and Ga doping, as indicated by X-ray photoelectron spectroscopy analysis. The total resistances of single TiO2 nanotube devices with EBAD- or IBAD-Pt interconnections were 3.82 × 1010 and 4.76 × 108 Ω, respectively. When the resistivity of a single nanotube is low, the high series resistance of EBAD-Pt cannot be ignored. IBAD is a suitable method for nanotechnology applications, such as photocatalysis and biosensors.

  8. Environmentally stable sputter-deposited thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, D.J.

    1978-03-01

    Accelerated corrosion data are presented for the titanium-silver and chrome-gold thin film metallization systems presently used at Sandia Laboratories. Improvements in corrosion, hence reliability, as a result of interposing a thin intermediate layer of either platinum or palladium are shown. Potentiometric measurements showing the alteration of corrosion potential with the use of palladium for the titanium-silver system are also presented.

  9. Magnetic properties of ultrathin discontinuous Co/Pt multilayers: Comparison with short-range ordered and isotropic CoPt3 films

    Science.gov (United States)

    Charilaou, M.; Bordel, C.; Berche, P.-E.; Maranville, B. B.; Fischer, P.; Hellman, F.

    2016-06-01

    Magnetic properties of thin Co/Pt multilayers have been investigated in order to study the dependence of magnetization M , uniaxial anisotropy Ku, and Curie temperature TC on the multilayer thickness, composition, and structure. A comparison between epitaxial submonolayer multilayers and epitaxial fcc CoPt3 alloy films with large perpendicular magnetic anisotropy (PMA) attributed to growth-induced Co clustering reveals significant differences in the temperature dependence of magnetization M (T ) , despite the presence of thin planar Co platelets in both cases. Even the thinnest discontinuous multilayered structure shows a Langevin-like M (T ) , while the alloy films with PMA show a broadened and enhanced M (T ) indicating a distribution of environments, including monolayer Co platelets separated by only 1-2 layers of Pt. These differences have been reproduced in Monte Carlo simulations, and are shown to be due to different distributions of Co-Co and Co-Pt nearest neighbors. The relatively uniform Co-Co coordination of even a discontinuous rough multilayer produces a Langevin-like M (T ) , whereas the broader distribution associated with platelets in the PMA films results in a nearly linear T dependence of M .

  10. Edge-modulated perpendicular magnetic anisotropy in [Co/Pd]n and L10-FePt thin film wires

    Science.gov (United States)

    Zhang, Jinshuo; Ho, Pin; Currivan-Incorvia, Jean Anne; Siddiqui, Saima A.; Baldo, Marc A.; Ross, Caroline A.

    2015-11-01

    Thickness modulation at the edges of nanostructured magnetic thin films is shown to have important effects on their perpendicular magnetic anisotropy. Thin film wires with tapered edges were made from [Co/Pd]20 multilayers or L10-FePt films using liftoff with a double-layer resist. The effect of edge taper on the reversal process was studied using magnetic force microscopy and micromagnetic modeling. In [Co/Pd]20, the anisotropy was lower in the tapered edge regions which switched at a lower reverse field compared to the center of the wire. The L10-FePt wires showed opposite behavior with the tapered regions exhibiting higher anisotropy.

  11. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Serhane, Rafik, E-mail: rserhane@cdta.dz [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Hassein-Bey, Abdelkadder [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Micro and Nano Physics Group, Faculty of Sciences, University Saad Dahlab of Blida (USDB), BP. 270, DZ-09000 Blida (Algeria); Boutkedjirt, Tarek [Equipe de Recherche Physique des Ultrasons, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, DZ-16111 Algiers (Algeria)

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO{sub 2}/Si and Al (1 1 1)/SiO{sub 2}/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as K{sub eff}{sup 2}=5.09%, with a quality factor Q{sub r} = 1001.4.

  12. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Science.gov (United States)

    Serhane, Rafik; Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid; Hassein-Bey, Abdelkadder; Boutkedjirt, Tarek

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO2/Si and Al (1 1 1)/SiO2/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as Keff2    =    5 .0 9 %, with a quality factor Qr = 1001.4.

  13. Electrolysis of ammonia for hydrogen production catalyzed by Pt and Pt-Ir deposited on nickel foam

    Institute of Scientific and Technical Information of China (English)

    Min; Jiang; Dandan; Zhu; Xuebo; Zhao

    2014-01-01

    Electrolysis of ammonia in alkaline electrolyte solution was applied for the production of hydrogen. Both Pt-loaded Ni foam and Pt-Ir loaded Ni foam electrodes were prepared by electrodeposition and served as anode and cathode in ammonia electrolytic cell, respectively. The electrochemical behaviors of ammonia in KOH solution were individually investigated via cyclic voltammetry on three electrodes, i.e. bare Ni foam electrode, Pt-loaded Ni foam electrode and Pt-Ir loaded Ni foam electrode. The morphology and composition of the prepared Ni foam electrode were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). Effects of the concentration of electrolyte solution and temperature of electrolytic cell on the electrolysis reaction were examined in order to enhance the efficiency of ammonia electrolysis. The competition of ammonia electrolysis and water electrolysis in the same alkaline solution was firstly proposed to explain the changes of cell voltage with the electrolysis proceeding. At varying current densities, different cell voltages could be obtained from galvanostatic curves.The low cell voltage of 0.58 V, which is less than the practical electrolysis voltage of water(1.6 V), can be obtained at a current density of2.5 mA/cm2. Based on some experimental parameters, such as the applied current, the resulting cell voltage and output of hydrogen gas, the power consumption per gram of H2produced can be estimated.

  14. MOKE spectroscopy of FePtCu thin films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Fronk, Michael; Smykalla, Lars; Brombacher, Christoph; Schubert, Christian; Albrecht, Manfred; Salvan, Georgeta [Chemnitz University of Technology (Germany)

    2010-07-01

    Since the uniaxial magnetic anisotropy of FePt in its chemically ordered L1{sub 0} phase can reach 10 MJ/m{sup 3} FePt is considered to be a promising material for future magnetic storage devices. In this work Fe{sub 52}Pt{sub 48}(5 nm-x)/Cu(x) bilayers have been sputter deposited at room temperature onto thermally oxidized Si wafers and afterwards annealed to various temperatures between 450 C and 800 C under N{sub 2} atmosphere using a commercial rapid thermal annealing (RTA) setup. The RTA procedure leads to the formation of a ternary FePtCu alloy with pronounced perpendicular magnetic anisotropy. The dependence of both the coercivity and remanence extracted from polar MOKE hysteresis loops at 1.96 eV on the annealing temperature will be discussed with respect to the initial Cu thicknesses of 0.5 nm and 0.9 nm. In addition, MOKE-spectroscopy in the energy range between 1.7 eV and 5.5 eV was performed and a clear dependence on the initial Cu thickness and the annealing temperature is found. In some of the spectra the main spectral feature at around 2 eV exhibits a fine structure, which could be caused by the coexistence of the two crystalline phases and/or by the presence of defect sites.

  15. Asymmetry of Polarization Reversal and Current-Voltage Characteristics of Pt/PZT-Film/Pt:Ti/SiO2/Si-Substrate Structures

    Directory of Open Access Journals (Sweden)

    S. L. Bravina

    2011-01-01

    Full Text Available The characterization of the asymmetries of bipolar charge-voltage and current-voltage loops of polarization reversal and unipolar current-voltage curves for Pt/PZT-film/Pt:Ti/SiO2/Si-substrate systems was performed in the dynamic mode. The asymmetry of local deformation-voltage loops was observed by piezoresponse force microscopy. The comparison of the dependences of introduced asymmetry factors for the bipolar charge-voltage and current-voltage loops and unipolar current-voltage curves on drive voltage indicates the interconnection of ferroelectric and electrical space charge transfer asymmetries.

  16. In situ measurement of conductivity during nanocomposite film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Blattmann, Christoph O.; Pratsinis, Sotiris E., E-mail: sotiris.pratsinis@ptl.mavt.ethz.ch

    2016-05-15

    Highlights: • Flame-made nanosilver dynamics are elucidated in the gas-phase & on substrates. • The resistance of freshly depositing nanosilver layers is monitored. • Low T{sub g} polymers facilitate rapid synthesis of conductive films. • Conductive nanosilver films form on top of or within the polymer depending on MW. - Abstract: Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (T{sub g}) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing T{sub g}. Proper selection of the host polymer in combination with in situ resistance

  17. Electrochemically deposited Pd-Pt and Pd-Au codeposits on graphite electrodes for electrocatalytic H2O2 reduction.

    Science.gov (United States)

    Nagaiah, Tharamani Chikka; Schäfer, Dominik; Schuhmann, Wolfgang; Dimcheva, Nina

    2013-08-20

    Improved electrocatalytic activity and selectivity for the reduction of H2O2 were obtained by electrodepositing Pd-Pt and Pd-Au on spectrographic graphite from solutions containing salts of the two metals at varying ratio. The electrocatalytic activity of the resulting binary codeposits for H2O2 reduction was evaluated by means of the redox-competition mode of scanning electrochemical microscopy (SECM) and voltammetric methods. In a potential range from 0 to -600 mV (vs. Ag/AgCl/3 M KCl) at pH 7.0 in 0.1 M phosphate citrate buffer, the electrocatalytic activity of both Pd-Pt and Pd-Au codeposits was substantially improved as compared with the identically deposited single metals suggesting an electrocatalytic synergy of the codeposits. Pd-Pt and Pd-Au codeposits were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Codepositing with Au caused a change of hedgehog-like shaped Pd nanoparticles into cauliflower-like nanoparticles with the particle size decreasing with increasing Au concentration. Codepositing Pd with Pt caused the formation of oblong structures with the size initially increasing with increasing Pt content. However, the particle size decreases with further increase in Pt concentration. The improved electrocatalytic capability for H2O2 reduction of the Pd-Pt electrodeposits on graphite was further demonstrated by immobilizing glucose oxidase as a basis for the development of an interference-free amperometric glucose biosensor.

  18. Fundamental Mechanisms of Roughening and Smoothing During Thin Film Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Headrick, Randall [Univ. of Vermont, Burlington, VT (United States)

    2016-03-18

    In this research program, we have explored the fundamental limits for thin film deposition in both crystalline and amorphous (i.e. non-crystalline) materials systems. For vacuum-based physical deposition processes such as sputter deposition, the background gas pressure of the inert gas (usually argon) used as the process gas has been found to be a key variable. Both a roughness transition and stress transition as a function of pressure have been linked to a common mechanism involving collisions of energetic particles from the deposition source with the process inert gas. As energetic particles collide with gas molecules in the deposition process they lose their energy rapidly if the pressure (and background gas density) is above a critical value. Both roughness and stress limit important properties of thin films for applications. In the area of epitaxial growth we have also discovered a related effect; there is a critical pressure below which highly crystalline layers grow in a layer-by-layer mode. This effect is also though to be due to energetic particle thermalization and scattering. Several other important effects such as the observation of coalescence dominated growth has been observed. This mode can be likened to the behavior of two-dimensional water droplets on the hood of a car during a rain storm; as the droplets grow and touch each other they tend to coalesce rapidly into new larger circular puddles, and this process proceeds exponentially as larger puddles overtake smaller ones and also merge with other large puddles. This discovery will enable more accurate simulations and modeling of epitaxial growth processes. We have also observed that epitaxial films undergo a roughening transition as a function of thickness, which is attributed to strain induced by the crystalline lattice mismatch with the substrate crystal. In addition, we have studied another physical deposition process called pulsed laser deposition. It differs from sputter deposition due to the

  19. Structure and Morphology of Phthalocyanine Films Grown in Electrical Fields by Vapor Deposition

    Science.gov (United States)

    Zhu, Shen; Banks, C. E.; Frazier, D. O.; Penn, B.; Abdeldayem, H.; Hicks, R.; Burns, H. D.; Thompson, G. W.

    1999-01-01

    Phthalocyanine (Pc) films have been synthesized by vapor deposition on quartz substrates, some of which were coated with a very thin gold film before depositing Pc films. Electrical fields up to 6200 V/cm between a mech electrode and the substrate are introduced during film growth. These films have been characterized by x-ray diffraction and scanning electron microscopy. The molecular orientations and surface morphology of Pc films were changed under the electrical fields. The surface of these films grown without electrical field shows whisk-like morphology. When films are deposited under an electrical field, a dense film with flat surface is obtained.

  20. Pt/In2S3/CdS/Cu2ZnSnS4 Thin Film as an Efficient and Stable Photocathode for Water Reduction under Sunlight Radiation.

    Science.gov (United States)

    Jiang, Feng; Gunawan; Harada, Takashi; Kuang, Yongbo; Minegishi, Tsutomu; Domen, Kazunari; Ikeda, Shigeru

    2015-10-28

    An electrodeposited Cu2ZnSnS4 (CZTS) compact thin film modified with an In2S3/CdS double layer and Pt deposits (Pt/In2S3/CdS/CZTS) was used as a photocathode for water splitting of hydrogen production under simulated sunlight (AM 1.5G) radiation. Compared to platinized electrodes based on a bare CZTS film (Pt/CZTS) and a CZTS film modified with a CdS single layer (Pt/CdS/CZTS), the Pt/In2S3/CdS/CZTS electrode exhibited a significantly high cathodic photocurrent. Moreover, the coverage of the In2S3 layer was found to be effective for stabilization against degradation induced by photocorrosion of the CdS layer. Bias-free water splitting with a power conversion efficiency of 0.28% was achieved by using a simple two-electrode cell consisting of the Pt/In2S3/CdS/CZTS photocathode and a BiVO4 photoanode.

  1. Chemical Vapor Deposition of Aluminum Oxide Thin Films

    Science.gov (United States)

    Vohs, Jason K.; Bentz, Amy; Eleamos, Krystal; Poole, John; Fahlman, Bradley D.

    2010-01-01

    Chemical vapor deposition (CVD) is a process routinely used to produce thin films of materials via decomposition of volatile precursor molecules. Unfortunately, the equipment required for a conventional CVD experiment is not practical or affordable for many undergraduate chemistry laboratories, especially at smaller institutions. In an effort to…

  2. Protection of elastomers with DLC film : deposition, characterization and performance

    NARCIS (Netherlands)

    Martinez Martinez, Diego

    2017-01-01

    Elastomers are materials which suffer from strong wear and cause high friction losses when subjected to dynamic contact, leading quite often to failure of the components in devices. In this Thesis, the protection of elastomers by the deposition of carbon-based films (DLC) is studied. To accomplish t

  3. Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

    DEFF Research Database (Denmark)

    Tricoli, Antonio; Elmøe, Tobias Dokkedal

    2012-01-01

    The assembly of nanoparticle films by flame spray pyrolysis (FSP) synthesis and deposition on temperature‐controlled substrates (323–723 K) was investigated for several application‐relevant conditions. An exemplary SnO2 nanoparticle aerosol was generated by FSP and its properties (e.g., particle...

  4. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    OpenAIRE

    John Meynard M. Tengco; Bahareh Alsadat Tavakoli Mehrabadi; Yunya Zhang; Akkarat Wongkaew; John R. Regalbuto; Weidner, John W.; John R. Monnier

    2016-01-01

    Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED) of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) characterization of the base catalyst showed highly dispersed particles. A basic E...

  5. Ultrathin Coating of Confined Pt Nanocatalysts by Atomic Layer Deposition for Enhanced Catalytic Performance in Hydrogenation Reactions.

    Science.gov (United States)

    Wang, Meihua; Gao, Zhe; Zhang, Bin; Yang, Huimin; Qiao, Yan; Chen, Shuai; Ge, Huibin; Zhang, Jiankang; Qin, Yong

    2016-06-13

    Metal-support interfaces play a prominent role in heterogeneous catalysis. However, tailoring the metal-support interfaces to realize full utilization remains a major challenge. In this work, we propose a graceful strategy to maximize the metal-oxide interfaces by coating confined nanoparticles with an ultrathin oxide layer. This is achieved by sequential deposition of ultrathin Al2 O3 coats, Pt, and a thick Al2 O3 layer on carbon nanocoils templates by atomic layer deposition (ALD), followed by removal of the templates. Compared with the Pt catalysts confined in Al2 O3 nanotubes without the ultrathin coats, the ultrathin coated samples have larger Pt-Al2 O3 interfaces. The maximized interfaces significantly improve the activity and the protecting Al2 O3 nanotubes retain the stability for hydrogenation reactions of 4-nitrophenol. We believe that applying ALD ultrathin coats on confined catalysts is a promising way to achieve enhanced performance for other catalysts.

  6. YBCO thin film evaporation on as-deposited silver film on MgO

    Science.gov (United States)

    Azoulay, J.

    1999-11-01

    YBa 2Cu 3O 7- δ (YBCO) thin film was evaporated on as-deposited Ag buffer layer on MgO substrate. A simple, inexpensive vacuum system equipped with one resistively heated source was used. The subsequent heat treatment was carried out under low oxygen partial pressure at a relatively low temperature and short dwelling time. The films thus obtained were characterized for electrical properties using DC four-probe electrical measurements and inspected for structural properties and chemical composition by scanning electron microscopy (SEM). It is shown that YBCO thin film can grow on as-deposited thin silver layer on MgO substrate.

  7. First principles investigation of the activity of thin film Pt, Pd and Au surface alloys for oxygen reduction

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Hansen, Heine Anton; Rossmeisl, Jan;

    2015-01-01

    active binary thin films are near-surface alloys of Pt with subsurface Pd and certain PdAu and PtAu thin films with surface and/or subsurface Au. The most active ternary thin films are with pure metal Pt or Pd skins with some degree of Au in the surface and/or subsurface layer and the near-surface alloys...... of Au with mixed Pt/Pd skins. The activity of the binary and ternary catalysts is explained through weakening of the OH binding energy caused by solute elements. However, given the low alloy formation energies it may be difficult to tune and retain the composition under operating conditions....... This is particularly challenging for alloys containing Au due to a high propensity of Au to segregate to the surface. We also show that once Au is on the surface it will diffuse to defect sites, explaining why small amounts of Au retard dissolution of Pt nanoparticles. For the PtPd thin films there is no pronounced...

  8. Annealing effects on the properties of amorphous CoSiB/Pt multilayer films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sol; Park, Jisun; Yim, Haein [Sookmyung Women' s University, Seoul (Korea, Republic of); Kim, Taewan [Sejong University, Seoul (Korea, Republic of)

    2014-01-15

    The perpendicular magnetic anisotropy (PMA) of amorphous CoSiB/Pt multilayer systems was studied as a function of the thickness of the CoSiB/Pt bilayer and the number of repeated CoSiB/Pt bilayers. In this letter, we investigate the thermal property of a CoSiB single layer film annealed at 150 ∼ 350 .deg. C for 3 hours and the perpendicular magnetic anisotropic property of amorphous ferromagnetic Ta(50 A)/Pt(30 A)/[CoSiB(2, 3, 4, 5, 6 A)/Pt(14 A)]5/Ta(50 A) multilayer films annealed at 200 ∼ 400 .deg. C for 3 hours. The thermal properties were measured by using a differential scanning calorimeter and an X-ray diffractometer, and the magnetic properties were measured by using a vibrating sample magnetometer. The PMA of the CoSiB/Pt multilayer film disappeared and the multilayer film show isotropy after annealing at a temperature of 350 .deg. C or above.

  9. Silicon Nitride Film Deposition by Photochemical Vapor Deposition Using an Argon Excimer Lamp

    Science.gov (United States)

    Maezono, Yoshinari; Toshikawa, Kiyohiko; Kurosawa, Kou; Amari, Kouichi; Ishimura, Sou; Katto, Masahito; Yokotani, Atsushi

    2007-06-01

    In this paper, we report the deposition of silicon nitride (SiNx) films for the production of semiconductor devices and flat panel displays, by chemical vapor deposition with vacuum ultraviolet excimer lamps (VUV-CVD) using SiH4 and NH3 as raw materials. An Ar2* excimer lamp (λ=126 nm, hν=9.8 eV) with a high photon energy was used to directly excite and dissociate SiH4 through a photochemical reaction. SiNx films were successfully formed at a low temperature of 100 °C with the Ar2* excimer lamp. Although the Si-rich films were obtained using an Ar2* lamp, they showed a quality almost similar to that of films obtained by conventional plasma-CVD at 400 °C.

  10. Low resistance polycrystalline diamond thin films deposited by hot filament chemical vapour deposition

    Indian Academy of Sciences (India)

    Mahtab Ullah; Ejaz Ahmed; Abdelbary Elhissi; Waqar Ahmed

    2014-05-01

    Polycrystalline diamond thin films with outgrowing diamond (OGD) grains were deposited onto silicon wafers using a hydrocarbon gas (CH4) highly diluted with H2 at low pressure in a hot filament chemical vapour deposition (HFCVD) reactor with a range of gas flow rates. X-ray diffraction (XRD) and SEM showed polycrystalline diamond structure with a random orientation. Polycrystalline diamond films with various textures were grown and (111) facets were dominant with sharp grain boundaries. Outgrowth was observed in flowerish character at high gas flow rates. Isolated single crystals with little openings appeared at various stages at low gas flow rates. Thus, changing gas flow rates had a beneficial influence on the grain size, growth rate and electrical resistivity. CVD diamond films gave an excellent performance for medium film thickness with relatively low electrical resistivity and making them potentially useful in many industrial applications.

  11. Control of native acceptor density in epitaxial Cu2O thin films grown by electrochemical deposition

    Science.gov (United States)

    Ashida, Atsushi; Sato, Shunsuke; Yoshimura, Takeshi; Fujimura, Norifumi

    2017-06-01

    Controlling the native carrier is essential for using Cu2O in devices such as solar cells. The origin of the native p-type carrier in Cu2O is thought to be copper vacancies (VCu). In this work, epitaxially grown Cu2O thin films were prepared by electrochemical deposition at a low temperature of 45 °C on a Pt (111) cathodic electrode. The sources of Cu and O for Cu2O were Cu2+ and OH- in the electrolyte and the ion concentrations were changed to control the stoichiometry of deposition and the density of VCu. The density of ionized acceptors (NA+) in the Cu2O films was evaluated by the C-V properties measured with Schottky electrodes. NA+ did not depend on [Cu2+], whereas NA+ increased with increasing [OH-] when [OH-] was larger than 10-3 mol/L (electrolyte pH >11) with [Cu2+] fixed at 10-1 mol/L. The ion concentration dependence of NA+ and the dependence of the total cathodic current density revealed that the generation of VCu was affected by a complex combination of the ion concentrations and film growth rate.

  12. Pyrolytic carbon film deposit as an electrochemical interface.

    Directory of Open Access Journals (Sweden)

    M. Hadi

    2009-02-01

    Full Text Available A pyrolytic carbon (PC film was grown on planar substrate (graphite rods by chemical vapor deposition from gaseous feed of methane using a vertical hot-wall deposition reactor. Scanning electron microscopy was used to study the surface structure. The PC film was also characterized by cyclic voltammetry technique to evaluate the background current, stability and the electrochemical response using ascorbic acid, Co(phen32+/3+ and Fe(CN6 3-/4- redox couplesand compared to glassy carbon (GC electrode. High degree of electrochemical activity and the enhanced signal to background (S/B ratio demonstrated that the PC film might be an attractive electrode material for electroanalytical measurements.

  13. Directed vapor deposition of lithium manganese oxide films

    Science.gov (United States)

    Jin, Sang-Wan

    Electron beam evaporation and sputtering techniques are used to fabricate multilayered thin film structures. However, these techniques suffer several drawbacks resulting from (i) the complex chemistries of the lithiated oxide layers used for the cathode and electrolyte, (ii) the need for precise microstructure control in systems with many metastable phases, and (iii) the low deposition rate and poor material utilization efficiency, which slows the application of this energy storage approach. This dissertation has investigated the use of a novel electron-beam directed vapor deposition (EB-DVD) method for the synthesis of thin film batteries. The dissertation focuses upon the cathode layer of a representative Li-ion thin film battery system and investigates in detail the deposition of lithium manganese oxide films. Many phases with offering various electrochemical performance exist in the Li-Mn-O system and the thesis also investigates the use of processing conditions to control the structure and composition of these cathode layers. In the EB-DVD approach, a high voltage electron beam is used to evaporate a source material in the throat of a nozzle that forms a coaxial transonic gas jet around the vapor. The gas jet entrains and transports the vapor to a substrate where the deposition occurs. Directed simulation of Monte Carlo (DSMC) methods indicated that the vapor plume could be matched to a substrate diameter, and the deposition rate (and vapor utilization efficiency) therefore controlled by adjusting the pressure ratio up and downstream of the nozzle opening in the deposition chamber, and by varying the gas jet density and speed. The highest deposition rates were obtained with a high pressure ratio and the gas jet density. These observations are found to be consistent with the experimental results. Deposition rates up to 16 nm/s could be achieved using the most effective gas entrainment conditions identified by DSMC calculation. This was about a factor of ten

  14. Structural and optical properties of tellurite thin film glasses deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Martin, D.; Fernandez-Navarro, J.M. [Laser Processing Group, Instituto de Optica (CSIC), Serrano 121, 28006 Madrid (Spain); Gonzalo, J., E-mail: j.gonzalo@io.cfmac.csic.es [Laser Processing Group, Instituto de Optica (CSIC), Serrano 121, 28006 Madrid (Spain); Jose, G.; Jha, A. [Institute for Materials Research, University of Leeds, Clarendon Road, Leeds LS2 9JT (United Kingdom); Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica (CSIC), Marie Curie s/n, 28049 Cantoblanco (Spain); Domingo, C. [Instituto de Estructura de la Materia (CSIC), Serrano 121, 28006 Madrid (Spain); Garcia-Lopez, J. [Centro Nacional de Aceleradores, P. Tecnologico ' Cartuja 93' , 41092 Sevilla (Spain)

    2011-10-31

    Tellurite (TeO{sub 2}-TiO{sub 2}-Nb{sub 2}O{sub 5}) thin film glasses have been produced by pulsed laser deposition at room temperature at laser energy densities in the range of 0.8-1.5 J/cm{sup 2} and oxygen pressures in the range of 3-11 Pa. The oxygen concentration in the films increases with laser energy density to reach values very close to that of the bulk glass at 1.5 J/cm{sup 2}, while films prepared at 1.5 J/cm{sup 2} and pressures above 5 Pa show oxygen concentration in excess of 10% comparing to the glass. X-ray photoelectron spectroscopy shows the presence of elementary Te in films deposited at O{sub 2} pressures {<=} 5 Pa that is not detected at higher pressures, while analysis of Raman spectra of the samples suggests a progressive substitution of TeO{sub 3} trigonal pyramids by TeO{sub 4} trigonal bipyramids in the films when increasing their oxygen content. Spectroscopic ellipsometry analysis combined with Cauchy and effective medium modeling demonstrates the influence of these compositional and structural modifications on the optical response of the films. Since the oxygen content determines their optical response through the structural modifications induced in the films, those can be effectively controlled by tuning the deposition conditions, and films having large n (2.08) and reduced k (< 10{sup -4}) at 1.5 {mu}m have been produced using the optimum deposition conditions.

  15. Dual ion beam deposition of carbon films with diamondlike properties

    Science.gov (United States)

    Mirtich, M. J.; Swec, D. M.; Angus, J. C.

    1984-01-01

    A single and dual ion beam system was used to generate amorphous carbon films with diamond like properties. A methane/argon mixture at a molar ratio of 0.28 was ionized in the low pressure discharge chamber of a 30-cm-diameter ion source. A second ion source, 8 cm in diameter was used to direct a beam of 600 eV Argon ions on the substrates (fused silica or silicon) while the deposition from the 30-cm ion source was taking place. Nuclear reaction and combustion analysis indicate H/C ratios for the films to be 1.00. This high value of H/C, it is felt, allowed the films to have good transmittance. The films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Although the measured density of the films was approximately 1.8 gm/cu cm, a value lower than diamond, the films exhibited other properties that were relatively close to diamond. These films were compared with diamondlike films generated by sputtering a graphite target.

  16. Pulsed laser deposition of nano-glassy carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Ossi, P.M. [Dip. Ingegneria Nucleare and Centre of Excellence, NanoEngineered Materials and Surfaces (NEMAS), Politecnico di Milano, via Ponzio, 34-3, 20133 Milan (Italy)]. E-mail: paolo.ossi@polimi.it; Bottani, C.E. [Dip. Ingegneria Nucleare and Centre of Excellence, NanoEngineered Materials and Surfaces (NEMAS), Politecnico di Milano, via Ponzio, 34-3, 20133 Milan (Italy); Miotello, A. [Dip. Fisica, Universita di Trento, 38050 Povo (TN) (Italy)

    2005-07-30

    Carbon films have been deposited at room temperature on (1 0 0) Si substrates by pulsed laser ablation (PLA) from a highly oriented pyrolitic graphite source. Changing the laser power density from 8.5 to 19 MW mm{sup -2} and using various ambient atmospheres (helium, argon from 0.6 Pa to 2 kPa), nano-sized cluster-assembled films were obtained. Scanning electron microscopy shows that the film morphology, changes with increasing ambient gas pressure. We observed in the sequence: dense columns, node-like morphology, platelets (only in argon) and an open dendritic structure. By atomic force microscopy, on representative films, we evaluated the size distribution and relative abundancy of aggregates of carbon clusters, as well as film roughness. Raman spectroscopy shows that all the films are sp{sup 2} coordinated, structurally disordered and belong to the family of carbon nano-glasses. The estimated film coherence length gives an average size of about 5 nm for the agglomerated carbon clusters in the films. The average number of carbon atoms per cluster depends on ambient gas pressure, but is nearly independent of laser intensity.

  17. Tailoring exchange bias through chemical order in epitaxial FePt3 films

    Science.gov (United States)

    Saerbeck, T.; Zhu, H.; Lott, D.; Lee, H.; LeClair, P. R.; Mankey, G. J.; Stampfl, A. P. J.; Klose, F.

    2013-07-01

    Intentional introduction of chemical disorder into mono-stoichiometric epitaxial FePt3 films allows to create a ferro-/antiferromagnetic two-phase system, which shows a pronounced and controllable exchange bias effect. In contrast to conventional exchange bias systems, granular magnetic interfaces are created within the same crystallographic structure by local variation of chemical order. The amount of the exchange bias can be controlled by the relative amount and size of ferromagnetic and antiferromagnetic volume fractions and the interface between them. The tailoring of the magnetic composition alone, without affecting the chemical and structural compositions, opens the way to study granular magnetic exchange bias concepts separated from structural artifacts.

  18. Effective conductivity of chemically deposited ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Robles, M. [Universidad Autonoma del Estado de Morelos (UAEM), Cuernavaca (Mexico). Fac. de Ciencias; Tagueena-Martinez, J. [IIM-UNAM, Temixco, Morelos (Mexico). Lab. de Energia Solar; Del Rio, J.A. [IIM-UNAM, Temixco, Morelos (Mexico). Lab. de Energia Solar

    1997-01-30

    Chemically deposited thin films have multiple applications. However, as a result of their complex structure, their physical properties are very difficult to predict. In this paper, we use an effective medium approach to model these heterogeneous systems. We extend Thorpe`s formula for the effective electrical conductivity of elliptical holes randomly distributed in a matrix to a system composed of conducting ellipses in a conducting matrix. This extension is used to calculate the effective electrical conductivity of polycrystalline chemically deposited ZnO thin films. We compare experimental results obtained by two different deposition methods: spray pyrolysis and successive ion layer adsorption and reaction (SILAR) reported here. We select the elliptical geometric parameters from microstructural data. Good agreement between the experimental measurements and our calculation is obtained. In addition, we present a new proof of the reciprocity theorem used to derive the theoretical relation. (orig.)

  19. L10 ordered phase formation in FePt, FePd, CoPt, and CoPd alloy thin films epitaxially grown on MgO(001) single-crystal substrates

    Science.gov (United States)

    Ohtake, Mitsuru; Ouchi, Shouhei; Kirino, Fumiyoshi; Futamoto, Masaaki

    2012-04-01

    The FePt, FePd, CoPt, and CoPd epitaxial thin films are prepared on MgO(001) single-crystal substrates by ultrahigh vacuum RF magnetron sputtering. The effects of the magnetic material and the substrate temperature on the film growth, the film structure, and the magnetic properties are investigated. The L10 ordered phase formation is observed for FePt, FePd, and CoPt films prepared at temperatures higher than 200, 400, and 600 °C, respectively, whereas that is not recognized for CoPd films. The L10-FePd(001) single-crystal films with the c-axis normal to the substrate surface are formed, whereas the FePt and CoPt epitaxial films include L10(100) crystals whose c-axis is parallel to the substrate surface, in addition to the L10(001) crystals. Upon increasing the substrate temperature, the ordering degree increases. A higher ordering parameter is observed in the order of FePd > FePt > CoPt. The magnetic properties are influenced by the crystal structure, the crystallographic orientation of the L10 crystal, and the ordering degree.

  20. Deposition of thermal and hot-wire chemical vapor deposition copper thin films on patterned substrates.

    Science.gov (United States)

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    In this work we study the hot-wire chemical vapor deposition (HWCVD) of copper films on blanket and patterned substrates at high filament temperatures. A vertical chemical vapor deposition reactor was used in which the chemical reactions were assisted by a tungsten filament heated at 650 degrees C. Hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) vapors were used, directly injected into the reactor with the aid of a liquid injection system using N2 as carrier gas. Copper thin films grown also by thermal and hot-wire CVD. The substrates used were oxidized silicon wafers on which trenches with dimensions of the order of 500 nm were formed and subsequently covered with LPCVD W. HWCVD copper thin films grown at filament temperature of 650 degrees C showed higher growth rates compared to the thermally ones. They also exhibited higher resistivities than thermal and HWCVD films grown at lower filament temperatures. Thermally grown Cu films have very uniform deposition leading to full coverage of the patterned substrates while the HWCVD films exhibited a tendency to vertical growth, thereby creating gaps and incomplete step coverage.

  1. Photocatalytic ability of TiO2 porous film prepared by modified spray pyrolysis deposition technique

    National Research Council Canada - National Science Library

    SUGIYAMA, Osamu; OKUYA, Masayuki; KANEKO, Shoji

    2009-01-01

    In a spray pyrolysis deposition (SPD) technique, deposition of film material and formation of surface structure are simultaneously occur, therefore, it is suitable for the preparation of microstructure-controlled thin films...

  2. Experimental investigation of off-stoichiometry and 3d transition metal (Mn, Ni, Cu-substitution in single-crystalline FePt thin films

    Directory of Open Access Journals (Sweden)

    Takuya Ono

    2016-05-01

    Full Text Available In L10 (fct-FePt thin films, both tuning Fe and Pt concentrations and substitution with third-metal were studied for magnetic characteristic optimization. We investigated single-crystalline FePt-X (X = Mn, Ni, Cu thin films grown epitaxially on MgO(001 substrates at a substrate temperature of 350  °C by changing Fe, Pt, and X contents, and explored the effects of off-stoichiometry and 3d-metal-substitution. The magnetic moment per atom (m of FePt-X films as a function of the effective number of valence electrons (neff in 3d metal sites follows the Slater-Pauling-type trend, by which m decreases by the neff deviation from neff = 8, independently of the X metal and the Pt concentration. The magnetic anisotropy (Ku exhibits neff dependence similar to m. This trend was almost independent of the Pt concentration after compensation using the theoretical prediction on the relation between Ku and Fe/Pt concentrations. Such a trend has been proved for stoichiometric FePt-X films, but it was clarified as robust against off-stoichiometry. The compensated Ku ( K u comp of FePt-Mn and FePt-Cu followed a similar trend to that predicted by the rigid-band model, although the K u comp of the FePt-Mn thin films dropped more rapidly than the rigid band calculation. However, it followed the recent first-principles calculation.

  3. Experimental investigation of off-stoichiometry and 3d transition metal (Mn, Ni, Cu)-substitution in single-crystalline FePt thin films

    Science.gov (United States)

    Ono, Takuya; Nakata, Hitoshi; Moriya, Tomohiro; Kikuchi, Nobuaki; Okamoto, Satoshi; Kitakami, Osamu; Shimatsu, Takehito

    2016-05-01

    In L10 (fct)-FePt thin films, both tuning Fe and Pt concentrations and substitution with third-metal were studied for magnetic characteristic optimization. We investigated single-crystalline FePt-X (X = Mn, Ni, Cu) thin films grown epitaxially on MgO(001) substrates at a substrate temperature of 350 °C by changing Fe, Pt, and X contents, and explored the effects of off-stoichiometry and 3d-metal-substitution. The magnetic moment per atom (m) of FePt-X films as a function of the effective number of valence electrons (neff) in 3d metal sites follows the Slater-Pauling-type trend, by which m decreases by the neff deviation from neff = 8, independently of the X metal and the Pt concentration. The magnetic anisotropy (Ku) exhibits neff dependence similar to m. This trend was almost independent of the Pt concentration after compensation using the theoretical prediction on the relation between Ku and Fe/Pt concentrations. Such a trend has been proved for stoichiometric FePt-X films, but it was clarified as robust against off-stoichiometry. The compensated Ku ( Ku comp ) of FePt-Mn and FePt-Cu followed a similar trend to that predicted by the rigid-band model, although the Ku comp of the FePt-Mn thin films dropped more rapidly than the rigid band calculation. However, it followed the recent first-principles calculation.

  4. Annealing dependence of residual stress and optical properties of TiO2 thin film deposited by different deposition methods.

    Science.gov (United States)

    Chen, Hsi-Chao; Lee, Kuan-Shiang; Lee, Cheng-Chung

    2008-05-01

    Titanium oxide (TiO(2)) thin films were prepared by different deposition methods. The methods were E-gun evaporation with ion-assisted deposition (IAD), radio-frequency (RF) ion-beam sputtering, and direct current (DC) magnetron sputtering. Residual stress was released after annealing the films deposited by RF ion-beam or DC magnetron sputtering but not evaporation, and the extinction coefficient varied significantly. The surface roughness of the evaporated films exceeded that of both sputtered films. At the annealing temperature of 300 degrees C, anatase crystallization occurred in evaporated film but not in the RF ion-beam or DC magnetron-sputtered films. TiO(2) films deposited by sputtering were generally more stable during annealing than those deposited by evaporation.

  5. Vacuum deposition onto webs, films and foils

    CERN Document Server

    Bishop, Charles A

    2011-01-01

    Roll-to-roll vacuum deposition is the technology that applies an even coating to a flexible material that can be held on a roll and provides a much faster and cheaper method of bulk coating than deposition onto single pieces or non-flexible surfaces, such as glass. This technology has been used in industrial-scale applications for some time, including a wide range of metalized packaging (e.g. snack packets). Its potential as a high-speed, scalable process has seen an increasing range of new products emerging that employ this cost-effective technology: solar energy products are moving from rigid panels onto flexible substrates, which are cheaper and more versatile; in a similar way, electronic circuit 'boards' can be produced on a flexible polymer, creating a new range of 'flexible electronics' products; and, flexible displays are another area of new technology in vacuum coating, with flexible display panels and light sources emerging. Charles Bishop has written this book to meet the need he identified, as a t...

  6. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition

    OpenAIRE

    Ponja, S. D.; Sehmi, S. K.; Allan, E.; MacRobert, A. J.; Parkin, I. P.; Carmalt, C. J.

    2015-01-01

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activit...

  7. High conductivity transparent carbon nanotube films deposited from superacid

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, David S; Lee, Roland; Hu Liangbing [Unidym Incorporated, 1244 Reamwood Drive, Sunnyvale, CA 94089 (United States); Heintz, Amy M; Moore, Bryon; Cucksey, Chad; Risser, Steven, E-mail: dhecht@gmail.com [Battelle, 505 King Avenue, Columbus, OH 43201 (United States)

    2011-02-18

    Carbon nanotubes (CNTs) were deposited from a chlorosulfonic superacid solution onto PET substrates by a filtration/transfer method. The sheet resistance and transmission (at 550 nm) of the films were 60 {Omega}/sq and 90.9% respectively, which corresponds to a DC conductivity of 12 825 S cm{sup -1} and a DC/optical conductivity ratio of 64.1. This is the highest DC conductivity reported for CNT thin films to date, and attributed to both the high quality of the CNT material and the exfoliation/doping by the superacid. This work demonstrates that CNT transparent films have not reached the conductivity limit; continued improvements will enable these films to be used as the transparent electrode for applications in solid state lighting, LCD displays, touch panels, and photovoltaics.

  8. High conductivity transparent carbon nanotube films deposited from superacid.

    Science.gov (United States)

    Hecht, David S; Heintz, Amy M; Lee, Roland; Hu, Liangbing; Moore, Bryon; Cucksey, Chad; Risser, Steven

    2011-02-18

    Carbon nanotubes (CNTs) were deposited from a chlorosulfonic superacid solution onto PET substrates by a filtration/transfer method. The sheet resistance and transmission (at 550 nm) of the films were 60 Ω/sq and 90.9% respectively, which corresponds to a DC conductivity of 12,825 S cm(-1) and a DC/optical conductivity ratio of 64.1. This is the highest DC conductivity reported for CNT thin films to date, and attributed to both the high quality of the CNT material and the exfoliation/doping by the superacid. This work demonstrates that CNT transparent films have not reached the conductivity limit; continued improvements will enable these films to be used as the transparent electrode for applications in solid state lighting, LCD displays, touch panels, and photovoltaics.

  9. Reactive sputtering deposition of SiO2 thin films

    Directory of Open Access Journals (Sweden)

    IVAN RADOVIC

    2008-01-01

    Full Text Available SiO2 layers were deposited in a UHV chamber by 1 keV Ar+ ion sputtering from a high purity silicon target, using different values of the oxygen partial pressure (5×10-6–2×10-4 mbar and of the ion beam current on the target (1.67–6.85 mA. The argon partial pressure during operation of the ion gun was 1×10-3 mbar. The substrate temperature was held at 550 °C and the films were deposited to a thickness of 12.5–150 nm, at a rate from 0.0018–0.035 nm s-1. Structural characterization of the deposited thin films was performed by Rutherford backscattering spectrometry (RBS analysis. Reactive sputtering was proved to be efficient for the deposition of silica at 550 °C, an oxygen partial pressure of 2×10-4 mbar (ion beam current on the target of 5 mA or, at a lower deposition rate, ion beam current of 1.67 mA and an oxygen partial pressure of 6×10-5 mbar. One aspect of these investigations was to study the consumption of oxygen from the gas cylinder, which was found to be lower for higher deposition rates.

  10. Giant isothermal entropy change In (111)-oriented PMN-PT thin film

    Science.gov (United States)

    Hamad, Mahmoud A.

    2014-11-01

    An isothermal entropy change of 240 nm (111)-oriented PMN-PT 65/35 film near the ferroelectric Curie temperature, relative cooling power (RCP) and change of heat capacity have been investigated. The extracted data characterized giant isothermal entropy change of more than 16 J/kg K in electric field shift ΔE of 455 kV cm-1, which is nearly twice than that found for PbZr0.95Ti0.05O3 thin film at 492 kV cm-1 near the Curie point. Furthermore, the RCP ≈ 700 J/kg and change of heat capacity ≈ 233 J/kg K in electric field shift ΔE of 747 kV cm-1.

  11. Atomic Layer Deposited Thin Films for Dielectrics, Semiconductor Passivation, and Solid Oxide Fuel Cells

    Science.gov (United States)

    Xu, Runshen

    , ultra-thin layer of encapsulating ZnS is coated on the surface of GaSb and GaSb/InAs substrates. The 2 nm-thick ZnS film is found to provide a long-term protection against reoxidation for one order and a half longer times than prior report