Papers by Keyword: PLD

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Authors: Xian Qi Wei, Yong Jie Wang, Ming Yang Zhang, Zhong Zhang
Abstract: ZnO thin films are grown on sapphire substrate by employing a Nd:YAG (1064nm) laser ablation in 1.3 Pa oxygen ambient. X-ray diffraction (XRD) and atomic force microscopy (AFM) observation show that as-grown thin film possess (0002) textured feature and form columnar inclined grains with a small size. The as-grown films show a little oxygen vacancies and Zn interstitial by the analysis of X-ray photoelectron spectroscopy (XPS) and Raman. The annealing treatment in oxygen ambient causes obvious improvement on the structure, surface morphology, compositions and optical properties by the analysis of XRD, AFM, XPS, Raman and photoluminescence (PL) spectra. It can be concluded that the increase of UV emission is oriented to the improvement of structure and decrease of intrinsic defects. The blue emission (430 nm) is attributed to the electronic transition from shallow donor level of Zn interstitial to top level of valence band.
Authors: Kenneth A. Jones, K. Xie, D.W. Eckart, M.C. Wood, V. Talyansky, R.D. Vispute, T. Venkatesan, K. Wongchotigul, Michael G. Spencer
Authors: Badrul Munir, Kim Kyoo Ho
Abstract: Gallium or sulphur additions in CuInSe2 were prepared using RF magnetron sputtering and pulsed laser deposition respectively. All of the observed thin films show a chalcopyrite structure with the S addition increases the favourable (112) peak. The optical absorption coefficients were slightly decreased. The films energy band gap could be shifted from 1.04 to 1.68eV by adjusting the mole ratio of S/(S+Se) and In/(In+Ga). It is possible to obtain the optimum energy band gap by adding S solute or Ga at a certain ratio in favour of Se and In respectively. It is also necessary to control the ratio of Ga and S additions and to retain a certain portion of In to provide better properties of CIS films.
Authors: Jacinto P. Borrajo, Pio González, Julia Serra, Sara Liste, Stefano Chiussi, Betty León, Alejandro de Carlos, Francisco M. Varela-Feria, Julian Martínez-Fernández, António Ramirez de Arellano-López
Abstract: There is a need to develop new tough bioactive materials capable to withstand high loads when implanted in the body and with improved fixation, which led to the production of bioactive coatings on metallic substrates. A new approach, which consists of biomorphic silicon carbide (SiC) coated with bioactive glass, was recently presented. This new material joins the high mechanical strength, lightness and porosity of biomorphic SiC, and the bioactive properties of PLD glass films. In this work, a multiple evaluation in terms of biocompatibility of this new material was carried out starting from the biomorphic SiC morphology and porosity, following with the bioactivity of the coatings in simulated body fluid, and ending with a deep biocompatibility study with MG-63 cells. Different ranges of porosity and pore size were offered by the biomorphic SiC depending on the starting wood. The PLD glassy coatings had a high bioactivity in vitro and both the biomorphic SiC coated and uncoated presented high levels of biocompatibility.
Authors: Nurhanna Badar, Norlida Kamarulzaman
Abstract: Aluminium Oxide (Al2O3) thin films have been widely used in many kinds of applications due to their excellent properties such as good mechanical strength, high abrasive and insulating characteristics. In this work, Al2O3 thin films are deposited on silicon (100) substrates using pulsed laser deposition (PLD). The deposition is done using different chamber environments. The crystal structure of the thin films is investigated using Grazing Incidence Diffraction (GID). The surface morphology and thicknesses of the thin films are studied by Field Emission Scanning Electron Microscopy (FESEM). The electrical current-voltage (I-V) characteristics of the thin films are measured using Signaton H150 Probe Station with Keithly 302 source measurement. It was found that the different process parameters greatly influenced the characteristics of the thin films obtained. FESEM images show high quality, smooth and dense films obtained using the PLD method. Generally, all films show rectifying behaviour.
Authors: Adele Carradò, Agnès Fabre, Laurent Barrallier, Nathalie Viart, Ion N. Mihailescu, Gabriel Socol, Sorin Grigorescu, Jacques Werckmann, S. Ciuca, M. Tarcolea
Abstract: The aim of this paper is the residual stress evaluation in dental implants and the improvement of adherence at the metal-ceramic interface. This study is focused on the development of a multi-layer system model of Hydroxyapatite/TiO2/Ti components. Our aim is to validate new methods of laser ablation deposition and sol-gel, by controlling the residual stresses and actual adherence to titanium substrates. We present a report of the growth of hydroxyapatite layers by PLD (pulsed laser deposition) and sol-gel deposition, and the measurement of their residual stresses.
Authors: Shigeki Sawamura, Naonori Sakamoto, De Sheng Fu, Kazuo Shinozaki, Hisao Suzuki, Naoki Wakiya
Abstract: Thermal stability of bottom electrode thin films (La0.5Sr0.5)CoO3 (LSCO) and (La0.6Sr0.4)MnO3 (LSMO) were investigated. The crystallization and surface morphology of the heterostructure were characterized using x-ray diffraction and atomic force microscopy. Resistivity of the LSCO thin film was 25 cm. However, the resistivity of LSCO thin film increases sharply with annealing temperature. The LSMO thin film has high resistivity (100 mcm). The film does not decompose after thermal processing at 900 °C. To confirm thermal stability, we examined the effect of post annealing at various temperatures on the morphology and resistivity. Results showed that LSMO has higher thermal stability than that of LSCO.
Authors: S.H. Kim, I.S. Byun, I.R. Hwang, J.S. Choi, B.H. Park, S. Seo, Man Jong Lee, D.H. Seo, E.J. Jeoung, D.-S. Suh, Y.S. Joung, I.K. Yoo
Abstract: Polycrystalline ZrO2 and yttria-stablilized ZrO2 thin films have been deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition methods. Pt/ZrO2/Pt and Pt/YSZ/Pt capacitor structures show giant conductivity switching behaviors which can be utilized for nonvolatile memory devices. Maximum on/off ratio of 106 and good endurance even after 105 times conductivity switching are observed in a typical Pt/ZrO2/Pt whose ZrO2 film has been deposited at 100 °C and an oxygen pressure of 50 mTorr. The Pt/ZrO2/Pt structure exhibits two ohmic behaviors in the low voltage region (V < 1.4 V) depending on the value of previously applied high voltage and Schottky-type conduction in the high voltage region (1.4 V < V < 8.9 V). It seems that conductivity switching behaviors in our Pt/ZrO2/Pt structure result from the changes in both the Schottky barrier and the bulk conductivity controlled by applied voltages. A Pt/YSZ/Pt capacitor structure has more stable reset voltage and current state than a Pt/ZrO2/Pt capacitor structure. Moreover, a Pt/YSZ/Pt capacitor structure shows higher Conductivity than a Pt/ZrO2/Pt capacitor structure, which may result from substitution of Y3+ ions for Zr4+ ions.
Authors: Ayuko Matsunaga, Yuuki Kitanaka, Ryotaro Inoue, Yuji Noguchi, Masaru Miyayama, Kenji Itaka
Abstract: High-quality La0.84Sr0.16Ga0.26Mg0.74O3-δ (LSGM) epitaxial thin films were successfully grown on (100)-SrTiO3 (STO) substrates at a temperature of 800 °C by a pulsed laser deposition (PLD) method with KrF excimer laser pulses at an ozone pressure of 1.3 × 103 Pa. X-ray diffraction rocking curve measurements showed that the LSGM films had a full-width at half-maximum (FWHM) value of 0.11 °for out-of-plane 002 reflection, which was smaller than that reported for LaGaO3 films grown by atomic layer deposition methods (0.18 o). The reciprocal spaces mapping of 103 refraction showed that the LSGM films had a slightly larger lattice parameter a (out-of-plane) of 0.393 nm than a// (in-plane) of 0.391 nm.
Authors: Xin Chun Wang, Yue Hong Peng, Man Cheng, Kai Hua Yue
Abstract: We usually adopt DSP and ARM to perform signal collection and processing. However, functions of DSP and ARM largely depend on the software. Parameter modulation of the software must account for sampling time partly. Moreover, software can not control complex peripheral logic circuit very well. The above problems render DSP and ARM containing big flaws in high-speed data collection and processing. Field-programmable Gate Array (FPGA) possesses the characteristics of timeliness, controllability and rapid processing speed. The paper designed a new circuit based on FPGA to obtain high-speed signal, and utilized FFT IP core in FPGA to perform spectral analysis with the help of digital signals from the circuit. The paper introduced the design based on FPGA and verified that it possesses good performance according to actual experiments.
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