Ca(1−x)NixO catalytic thin films prepared by pulsed laser deposition

1993 ◽  
Vol 8 (9) ◽  
pp. 2400-2403 ◽  
Author(s):  
X.L. Mao ◽  
D.L. Perry ◽  
R.E. Russo

Ca(1−x)NixO solid-solution films with varying stoichiometry have been prepared by pulsed laser deposition from sintered targets of NiO and CaO. X-ray diffraction data indicate that the films have the structure of sodium chloride. The lattice constants for different stoichiometries vary with film composition. Using the Madelung energy as the binding energy between anions and cations and assuming that nickel and calcium ions are distributed randomly in lattice sites, the lattice constants were calculated and found to compare with experimental results. This study investigated the compositional changes that occur during the target sintering process and the pulsed laser deposition of films. Using these data, a target composition can be prepared to produce Ca(1−x)NixO thin films with any desired lattice constant.

2002 ◽  
Vol 720 ◽  
Author(s):  
Costas G. Fountzoulas ◽  
Daniel M. Potrepka ◽  
Steven C. Tidrow

AbstractFerroelectrics are multicomponent materials with a wealth of interesting and useful properties, such as piezoelectricity. The dielectric constant of the BSTO ferroelectrics can be changed by applying an electric field. Variable dielectric constant results in a change in phase velocity in the device allowing it to be tuned in real time for a particular application. The microstructure of the film influences the electronic properties which in turn influences the performance of the film. Ba0.6Sr0.4Ti1-y(A 3+, B5+)yO3 thin films, of nominal thickness of 0.65 μm, were synthesized initially at substrate temperatures of 400°C, and subsequently annealed to 750°C, on LaAlO3 (100) substrates, previously coated with LaSrCoO conductive buffer layer, using the pulsed laser deposition technique. The microstructural and physical characteristics of the postannealed thin films have been studied using x-ray diffraction, scanning electron microscopy, and nano indentation and are reported. Results of capacitance measurements are used to obtain dielectric constant and tunability in the paraelectric (T>Tc) regime.


2010 ◽  
Vol 123-125 ◽  
pp. 375-378 ◽  
Author(s):  
Ram Prakash ◽  
Shalendra Kumar ◽  
Chan Gyu Lee ◽  
S.K. Sharma ◽  
Marcelo Knobel ◽  
...  

Ce1-xFexO2 (x=0, 0.01, 0.03 and 0.0 5) thin films were grown by pulsed laser deposition technique on Si and LaAlO3 (LAO) substrates. These films were deposited in vacuum and 200 mTorr oxygen partial pressure for both the substrates. These films were characterized by x-ray diffraction XRD and Raman spectroscopy measurements. XRD results reveal that these films are single phase. Raman results show F2g mode at ~466 cm-1 and defect peak at 489 cm-1 for film that deposited on LAO substrates, full width at half maximum (FWHM) is increasing with Fe doping for films deposited on both the substrates.


1992 ◽  
Vol 7 (10) ◽  
pp. 2639-2642 ◽  
Author(s):  
R.K. Singh ◽  
Deepika Bhattacharya ◽  
S. Sharan ◽  
P. Tiwari ◽  
J. Narayan

We have fabricated Ni3Al and NiAl thin films on different substrates by the pulsed laser deposition (PLD) technique. A high energy nanosecond laser beam was directed onto Ni–Al (NiAl, Ni3Al) targets, and the evaporated material was deposited onto substrates placed parallel to the target. The substrate temperature was varied between 300 and 400 °C, and the substrate-target distance was maintained at approximately 5 cm. The films were analyzed using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry. At energy densities slightly above the evaporation threshold, a slight enrichment of Al was observed, while at higher energy densities the film stoichiometry was close (<5%) to the target composition. Barring a few particles, the surface of the films exhibited a smooth morphology. X-ray and TEM results corroborated the formation of Ni3Al and NiAl films from similar target compositions. These films were characterized by small randomly oriented grains with grain size varying between 200 and 400 Å.


2021 ◽  
Vol 19 (10) ◽  
pp. 34-40
Author(s):  
B.Y. Taher ◽  
A.S. Ahmed ◽  
Hassan J. Alatta

In this study, CdO2 (1-X) AlX thin films were prepared by pulsed-laser deposition. The X-ray diffraction patterns reveal that the films were polycrystalline with a cubic structure, and the composition of the material changed from CdO at the target to CdO2 in the deposited thin films. The intensity of the diffraction peak (or the texture factor) decreases with increasing hkl and has a maximum value for the (111) plane, the interplanar distance and diffraction angle has a high deviation from the standard value for the (111) plane and. This deviation is affected by doping concentration and shows its highest deviation at a doping concentration of 0.1 wt.% for the (111) and (200), and the 0.3 and 0.5 wt.% for the (210) and (220) planes, respectively. The crystalline size take a less value at plane has a high texture factor that is (111) plane and decreases with increase the doping concentration.


2013 ◽  
Vol 710 ◽  
pp. 25-28 ◽  
Author(s):  
Xiao Qiang Kou ◽  
Ji Ming Bian ◽  
Zhi Kun Zhang

Vanadium dioxide (VO2) films were grown on c-and m-plane sapphire substrates by pulsed laser deposition (PLD) technique with VO2ceramic target. The VO2films with preferred growth orientation and uniform dense distribution have been achieved on both substrates, as confirmed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The terahertz (THz) transmission properties of VO2thin films were studied by terahertz time-domain spectroscopy (THz-TDS). The results indicate that the THz transmission properties of VO2films are strongly influenced by the sapphire substrate orientation, suggesting that VO2films are ideal material candidates for THz modulation.


2005 ◽  
Vol 19 (01n03) ◽  
pp. 533-535
Author(s):  
J. H. HAO ◽  
J. GAO

We have developed a process to grow SrTiO 3 ( STO ) thin films showing single (110) orientation directly on Si by means of pulsed laser deposition technique. The growth of STO films directly on Si has been described. The crystallinity of the grown STO films was characterized by X-ray diffraction analysis of θ-2θ scan and rocking curve. Our results may be of interest for better understanding of the growth based on the perovskite oxide thin films on silicon materials.


2000 ◽  
Vol 658 ◽  
Author(s):  
Trong-Duc Doan ◽  
Cobey Abramowski ◽  
Paul A. Salvador

ABSTRACTThin films of NdNiO3 were grown using pulsed laser deposition on single crystal substrates of [100]-oriented LaAlO3 and SrTiO3. X-ray diffraction and reflectivity, scanning electron microscopy, and atomic force microscopy were used to characterize the chemical, morphological and structural traits of the thin films. Single-phase epitaxial films are grown on LaAlO3 and SrTiO3 at 625°C in an oxygen pressure of 200 mTorr. At higher temperatures, the films partially decompose to Nd2NiO4 and NiO. The films are epitaxial with the (101) planes (orthorhombic Pnma notation) parallel to the substrate surface. Four in-plane orientational variants exist that correspond to the four 90° degenerate orientations of the film's [010] with respect to the in-plane substrate directions. Films are observed to be strained in accordance with the structural mismatch to the underlying substrate, and this leads, in the thinnest films on LaAlO3, to an apparent monoclinic distortion to the unit cell.


2011 ◽  
Vol 1292 ◽  
Author(s):  
Nobuyuki Iwata ◽  
Mark Huijben ◽  
Guus Rijnders ◽  
Hiroshi Yamamoto ◽  
Dave H. A. Blank

ABSTRACTThe CaFeOX(CFO) and LaFeO3(LFO) thin films as well as superlattices were fabricated on SrTiO3(100) substrates by pulsed laser deposition (PLD) method. The tetragonal LFO film grew with layer-by-layer growth mode until approximately 40 layers. In the case of CFO, initial three layers showed layer-by-layer growth, and afterward the growth mode was transferred to two layers-by-two layers (TLTL) growth mode. The RHEED oscillation was observed until the end of the growth, approximately 50nm. Orthorhombic twin CaFeO2.5 (CFO2.5) structure was obtained. However, it is expected that the initial three CFO layers are CaFeO3 (CFO3) with the valence of Fe4+. The CFO and LFO superlattice showed a step-terraces surface, and the superlattice satellite peaks in a 2θ-θ and reciprocal space mapping (RSM) x-ray diffraction (XRD) measurements, indicating that the clear interfaces were fabricated.


2011 ◽  
Vol 47 (4) ◽  
pp. 415-422 ◽  
Author(s):  
G. Balakrishnan ◽  
P. Kuppusami ◽  
S. Murugesan ◽  
E. Mohandas ◽  
D. Sastikumar

1993 ◽  
Vol 327 ◽  
Author(s):  
Randolph E. Treece ◽  
James S. Horwitz ◽  
Douglas B. Chrisey

AbstractThin films of diamond and diamond-like carbon (DLC) are technologically important materials that serve as hard, scratch resistant and chemically inert coatings for tools and optics. Recent calculations suggest that β-C3N4 should be harder than diamond. We have deposited carbon nitride (CNx) thin films by pulsed laser deposition. The films were grown from a graphite target in a nitrogen background. The nitrogen source was either (a) a N2 gas atmosphere, or (b) a N2+/N+ ion beam generated by a Kaufman ion gun. A wide range of deposition parameters were investigated, such as deposition pressure (0.3-900 mTorr N2), substrate temperature (50 and 600°C), and laser fluence (1-4 J/cm2) and laser repetition rate (1-10 Hz). The films have been characterized by Rutherford Backscattering Spectroscopy, thin-film X-ray diffraction, scanning electron microscopy, and micro-Raman spectroscopy. In general, the films were nitrogen deficient with a maximum nitrogen to carbon ratio (N/C) of 0.45 and a shift in the G band Raman peak consistent with amorphous CNx (a-CNx).


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