Nanostructured Gold Thin Films Prepared by Pulsed Laser Deposition

2004 ◽  
Vol 19 (3) ◽  
pp. 950-958 ◽  
Author(s):  
Eric Irissou ◽  
Boris Le Drogoff ◽  
Mohammed Chaker ◽  
Michel Trudeau ◽  
Daniel Guay

A structural and morphological study of nanostructured gold thin films prepared by pulsed laser deposition in the presence of several inert background gases (Ar, He, and N2) and at various pressures (from 10 mTorr to 1 Torr) and target-to-substrate distances (from 1 to 10 cm) is presented. Structural and morphological analyses were undertaken using semiquantitative x-ray diffraction, scanning tunneling microscopy, and transmission electron microscopy. For each set of deposition conditions, the kinetic energy of the neutral gold species [Au(I)] present in the plasma plume was determined by time-of-flight emission spectroscopy and used to characterize the plasma dynamics. It is shown that all films exhibit a transition from highly [111] oriented to polycrystalline as the Au(I) kinetic energy decreases. The polycrystalline phase ratio is close to 0% for Au(I) kinetic energy larger than approximately 3.0 eV/atom and approximately 86 ± 10% for Au(I) kinetic energy smaller than approximately 0.30 eV/atom, irrespective of the background gas atmosphere. The mean crystallite size of both phases and the mean roughness of the films also follow a unique relation with the Au(I) kinetic energy, independently of the nature of the background gas, and nanocrystalline films with crystallite size as small as 12 nm are obtained for Au(I) kinetic energy smaller than 0.3 eV/atom.

1998 ◽  
Vol 508 ◽  
Author(s):  
A. Piqué ◽  
R. C. Y. Auyeung ◽  
D. B. Chrisey ◽  
B. Justus ◽  
A. Huston ◽  
...  

AbstractHigh quality luminescent thin films of strontium sulfide (SrS) doped with rare earths have been grown using Pulsed Laser Deposition (PLD). SrS films ranging in thicknesses from 0.05 to 2 µm. were deposited on MgO (001) and glass substrates. Deposition parameters such as growth temperature and H2S background gas pressure were varied and their effect on the structure, morphology and luminescence of the films was evaluated. The PLD grown films all showed texture and were highly oriented when deposited on MgO substrates as determined by their XRD spectra. Optical microscopy, SEM and AFM analysis were used to study the films' surface morphology. The thermally and optically stimulated luminescence properties of these films were evaluated as well. The data indicates that these materials may be useful for optical data storage applications.


1996 ◽  
Vol 438 ◽  
Author(s):  
Peidong Yang ◽  
Z. John Zhang ◽  
Jiangtao Hu ◽  
Charles M. Lieber

AbstractThin films of diamond-like carbon have been grown by pulsed laser deposition using a Nd:YAG laser at 532 nm. Time-of-flight mass spectroscopy was used to investigate the effects of laser power density and background gas pressure on the plume characteristics including the species in the plume and the kinetic energy distribution of each species. We found that with increasing laser power density (1) the relative amount of C+ ions increases, (2) the kinetic energy distributions of C+ get broader and can be deconvoluted into fast and slow components, and (3) the kinetic energy of the fast component of C+ ions increases from several to 40 eV. The resistivity and the local carbon bonding in films grown under these same conditions were also characterized. It was found that there is direct correlation between the characteristics of fast part of C+ ions in the plume and the diamond-like properties of the thin films. Under optimal growth conditions diamond-like carbon films with a large fraction of sp3 bonding can be prepared, although the maximum fraction appears to saturate at 70%. The implications of these results are discussed.


1995 ◽  
Vol 388 ◽  
Author(s):  
R.-F. Xiao ◽  
L.C. Ng ◽  
H.B. Liao

AbstractA pulsed laser deposition technique has been used to grow silicon oxynitride (SiOxNy) thin films at low deposition temperatures (25°C - 300°C). the thin films were found to be quite smooth in surface morphology, extremely inert in chemical solution and highly transparent in the optical range of 0.3 μm to 5 μm. the refractive index was tunable between 1.4 - 2.1 by the addition of oxygen in substitution of nitrogen in the film, and the dielectric constant is much larger than the similar films grown by conventional chemical vapor deposition. the high quality of the SiOxNy films deposited at such low temperatures was resulted from the large kinetic energy carried by the impinging particles created by the ablation of a high-power pulsed excimer laser. the kinetic energy of the impinged particles on the substrate provides thermal energy for surface diffusion and relaxation.


2005 ◽  
Vol 901 ◽  
Author(s):  
Andrea Li Bassi ◽  
Carlo Spartaco Casari ◽  
Fabio Di Fonzo ◽  
Alessandro Bailini ◽  
Matteo Fusi ◽  
...  

AbstractThin films synthesized by assembling clusters present interesting chemical and physical properties and a large specific surface, and are appealing for functional applications (e.g. sensing and catalysis). Also, clusters supported on surfaces are interesting both for nanocatalysis applications and for fundamental research. By means of pulsed laser deposition (PLD) in a background atmosphere we can induce cluster aggregation in the ablation plume and control the deposition kinetic energy of the clusters. These phenomena depend on the plume expansion dynamics and their influence on the properties of the deposited films has been investigated as a function of the background gas mass and pressure. The control of these parameters permits variation of the film surface morphology, from a compact structure with a very smooth surface, to a film with a controlled roughness at the nanoscale, to an open, low density meso- and nanostructure characterized by a high fraction of voids and by a large specific area. Thin films of WOx, TiOx, Pd/PdO, and Ag were deposited and characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman spectroscopy. Post-deposition annealing permits control of the crystalline degree of the films, which in the case of tungsten and titanium oxide is found to depend on the original nanostructure, while a different degree of oxidation can be induced by controlling the amount of oxygen in the deposition chamber. In-situ scanning tunneling microscopy (STM) was employed to study the first stages of growth of W films on different substrates. This opens the possibility to tailor the material properties through the control of the building nano-units.


2019 ◽  
Vol 682 ◽  
pp. 24-28 ◽  
Author(s):  
V.H. Martínez-Landeros ◽  
N. Hernandez-Como ◽  
G. Gutierrez-Heredia ◽  
M.A. Quevedo-Lopez ◽  
F.S. Aguirre-Tostado

1997 ◽  
Vol 505 ◽  
Author(s):  
W. F. Brock ◽  
J. E. Krzanowski ◽  
R. E. Leuchtner ◽  
L. J. Legore ◽  
D. J. Frankel

ABSTRACTA study has been conducted on ZrC/VC alloy thin films prepared by both pulsed laser deposition (PLD) and RF magnetron sputtering. The phase formation, wear properties, and hardness of these thin films were examined. An alloy target comprised of 36% VC and 64% ZrC (atomic %) was used to deposit films at 200°, 2000°, and 400° C. The nominal film thickness was 0.6 μm. X-ray diffraction (XRD) analysis revealed these films were solid-solution alloys and showed a preference for (100) orientation for sputter-deposited films and a (110) orientation for laser deposition. More highly oriented films were obtained at elevated temperatures as evidenced by rocking curve measurements on the PLD films. The FWHM of the peaks ranged from 2.2° to 8.3° for films deposited at 400° C and 20° C, respectively.Using time-of-flight quadmpole mass spectrometry (TOFQMS), we performed plume diagnostics to measure particle energies and the thermalization effects of the background gas. In vacuum, typical ion energies ranged from ˜5–100 eV while the neutral atoms had kinetic energies from ˜1–5 eV. Our measurements show that the background gas can be used to selectively thermalize low mass components in the plume. From measured kinetic energies and collision effects of the gas, the changes in crystallographic structure of the alloy with pressure appear to result from collision-induced effects from condensation of the Zr atoms. This ‘heavy’ atom effect may be an important new processing parameter with which to adjust film morphology and crystal texture.


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