Crystal Quality and Orientation of Pulsed Laser Deposited Barium Titanate Thin Films

1998 ◽  
Vol 526 ◽  
Author(s):  
J. Gottmann ◽  
T. Klotzbücher ◽  
B. Vosseler ◽  
E. W. Kreutz
Keyword(s):  
Thin Films ◽  
Kinetic Energy ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
Oriented Growth ◽  
Axis Orientation ◽  
Film Forming ◽  
Gas Atmosphere ◽  
Krf Excimer Laser

AbstractKrF excimer laser radiation (λ=248 nm, τ=25 ns) is used for pulsed laser deposition of BaTiO3 thin films on Pt/Ti/Si multilayer substrates. The processing gas atmosphere consists of O2 at typical pressures of p=10-3-5·10-1 mbar. The investigations concentrate on the influence of the substrate temperature and the kinetic energy of the film forming particles on the crystalline structure and orientation of the growing films.X-ray diffraction measurements and polarization dependent micro Raman spectroscopy reveal oriented growth of the films with c-axis orientation normal to the substrate surface and [100] texture if the energy of the particles is > 60 eV, while at lower kinetic energies a [110] or [111] texture with partly a-axis orientation is preferred. The ferroelectricity and the dielectric constant of the films, as determined by polarization versus voltage (P-V) and capacitance versus voltage (C-V) impedance measurements, decreases with increasing kinetic energy of the film forming particles. This decrease of the dielectric properties correlates with the change of the preferred orientation and the crystalline quality of the films.

Control of a-Axis and c-AXIS Orientation of the YBa2Cu3O7−x Thin Films by Pulsed Laser Deposition

1992 ◽  
Vol 275 ◽  
Author(s):  
Gun Yong Sung ◽  
Jeong Dae Suh ◽  
Kwang Yong Kang ◽  
Jeong Yong Lee
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Ybco Film ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Layer Structures

ABSTRACTWe have investigated the effect of substrate temperatures ranging from 680 °C to 800 °C on the orientation of pulsed laser deposited YBa2Cu3O7−x.(YBCO) thin films on (100) LaAlO3 substrates. X-ray diffraction studies indicate that there is a progressive change in the dominant orientation of the films from c-axis oriented (c-axis perpendicular to the substrate surface) to a-axis oriented (a-axis perpendicular to the substrate surface) grown as the substrate temperature is lowered. Two YBCO bilayers, which are the a-axis oriented YBCO film on the top of c-axis oriented YBCO film (a/c) bilayer and c-axis oriented YBCO film on the top of a-axis oriented YBCO film (c/a) bilayer, have been grown by in situ two step pulsed laser deposition and were characterized by scanning electron microscopy (SEM), Rutherford backscattering (RBS) spectrum, x-ray diffraction (XRD), and Tc measurements. Through SEM and XRD studies, double layer structures of the a/c and c/a bilayers were confirmed indirectly.

Stability and Structural Characterization of Epitaxial NdNiO3 Films Grown by Pulsed Laser Deposition

2000 ◽  
Vol 658 ◽  
Author(s):  
Trong-Duc Doan ◽  
Cobey Abramowski ◽  
Paul A. Salvador
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Monoclinic Distortion

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.

Carbon Nitride Thin Films Grown by Pulsed Laser Deposition

1993 ◽  
Vol 327 ◽  
Author(s):  
Randolph E. Treece ◽  
James S. Horwitz ◽  
Douglas B. Chrisey
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Carbon Nitride ◽  
Ion Beam ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Deposition Parameters ◽  
Wide Range ◽  
Gas Atmosphere

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).

Preparation and microstructural characterization of Si(100) Ce1−x GdxO2−δ thin films prepared by pulsed laser deposition technique

2014 ◽  
Vol 32 (4) ◽  
pp. 541-546 ◽  
Author(s):  
P. Nagaraju ◽  
Y. Vijayakumar ◽  
D. Phase ◽  
V. Reddy ◽  
M. Ramana Reddy
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Microstructural Characterization ◽  
Laser Deposition ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Krf Excimer Laser

AbstractMicrostructural properties of Ce1-x GdxO2-δ (x = 0 to 0.3) thin films prepared by pulsed laser deposition technique were studied. The thin films were deposited on Si(100) substrate at a substrate temperature of 973 K at the oxygen partial pressure of 0.2 Pa using KrF excimer laser with energy of 220 mJ. The prepared thin films were characterized by X-ray diffraction, Raman spectroscopy and atomic force microscopy. X-ray diffraction analysis confirmed the polycrystalline nature of the thin films. Crystallite size, strain and dislocation density were calculated. The Raman studies revealed the formation of Ce-O with the systematic variation of peak intensity and full width half maxima depending on concentration of gadolinium dopant. The thickness of the films was estimated using Talystep profiler. The surface roughness was estiamted based on AFM.

Processing Effects on the Contact Resistance of Ion Beam Sputtered Silver on Highly Oriented C-Axis and A-Axis YBCO Films

1992 ◽  
Vol 275 ◽  
Author(s):  
M. Narbutovskih ◽  
J. Rosner ◽  
P. Merchant ◽  
R. D. Jacowitz
Keyword(s):  
Thin Films ◽  
Contact Resistance ◽  
Ion Beam ◽  
Substrate Surface ◽  
Amorphous Layer ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Ion Beam Etching ◽  
X Ray ◽  
Processing Effects

ABSTRACTThis paper reports on the processes used to achieve low resistance silver contacts to YBCO thin films that have either c-axis or a-axis orientation. Characterization by x-ray diffraction and TEM verified that these films are highly oriented with either the a or the c axis oriented perpendicular to the substrate surface. TEM examination of some of the Ag/YBCO interfaces reveals the presence of an amorphous layer. We will describe the effects of ion beam etching and RTA alloying on the contact resistivity for both orientations.

Mechanical properties of pulsed laser-deposited hydroxyapatite thin films for applications in biomedical implants

2002 ◽  
Vol 750 ◽  
Author(s):  
Hyunbin Kim ◽  
Yogesh K. Vohra ◽  
William R. Lacefield ◽  
Renato P. Camata
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Energy Density ◽  
Laser Energy ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Krf Excimer Laser ◽  
Average Size ◽  
Substrate Temperatures

ABSTRACTWe have obtained nanostructured hydroxyapatite thin films on titanium alloy substrates by pulsed laser deposition. Deposition was carried out using a KrF excimer laser (248 nm) with the energy density of 4 – 7 J/cm2 at substrate temperatures in the 550°C - 650°C range. The crystallinity of the coatings was probed by X-ray diffraction. Phase transitions from hydroxyapatite to other calcium phosphate compounds were observed with varying the substrate temperature during the growth process. Scanning electron microscopy revealed thin films made up of partially sintered nanoscale grains. The average size of nanoscale grains increased significantly with film thickness, suggesting a growth mechanism involving the coalescence of nanoscale grains. As the laser energy density increases, the hydroxyapatite crystallites in the coatings are oriented preferentially along the c-axis perpendicular to the substrate. Mechanical properties of the highly c-axis oriented coatings such as hardness and Young's modulus were studied by using nanoindentation technique.

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

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

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

Microstructural and Electrical Characterization of Barium Strontium Titanatebased Solid Solution Thin Films Deposited on Ceramic Substrates by Pulsed Laser Deposition

2002 ◽  
Vol 720 ◽  
Author(s):  
Costas G. Fountzoulas ◽  
Daniel M. Potrepka ◽  
Steven C. Tidrow
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Electrical Characterization ◽  
Field Variable ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Ceramic Substrates ◽  
Nominal Thickness

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.

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