Formation of the (La0.67Sr0.33)2MnO4 Phase in La–Sr–Mn–O Thin Films by Pulsed Laser Deposition

2000 ◽  
Vol 15 (7) ◽  
pp. 1524-1527 ◽  
Author(s):  
Y. H. Li ◽  
L. Salamanca-Riba ◽  
Y. Zhao ◽  
S. B. Ogale ◽  
R. Ramesh ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Mixed Valence ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Regular Pattern ◽  
Image Simulation ◽  
Transmission Electron ◽  
Composition And Structure ◽  
The Matrix

La0.67Sr0.33MnO3 thin films were grown on LaAlO3 substrate in vacuum using pulsed laser deposition to investigate the effect of changing oxygen content. Transmission electron microscopy studies showed that the epitaxial (La0.67Sr0.33)2MnO4 phase with K2NiF4 structure formed unexpectedly as a matrix with a square-shaped nanometer-sized MnO phase distributed in a regular pattern throughout the whole film like self-assembled quantum dots. The MnO phase grew epitaxially from the LaAlO3 substrate to the top of the film with no outgrowth. High-resolution image simulation indicated that Sr ions take up only positions in every other La layer in the (La0.67Sr0.33)2MnO4 structure. Basing our theory on the composition and structure of the matrix phase, we propose that it is possibly electron-doped with a mixed valence of Mn2+/Mn3+ instead of the Mn3+/Mn4+ as in the hole-doped case.

Epitaxial Growth of AlN Thin Films on Silicon and Sapphire by Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Breakdown Field ◽  
Transmission Electron ◽  
Uv Visible ◽  
Relationship Of

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films

The effect of target crystallography on the growth of Pb(Mg1/3Nb2/3)O3 thin films using pulsed laser deposition

1999 ◽  
Vol 14 (6) ◽  
pp. 2355-2358 ◽  
Author(s):  
M. H. Corbett ◽  
G. Catalan ◽  
R. M. Bowman ◽  
J. M. Gregg
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Growth Conditions ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Lead Magnesium

Pulsed laser deposition has been used to make two sets of lead magnesium niobate thin films grown on single-crystal h100j MgO substrates. One set was fabricated using a perovskite-rich target while the other used a pyrochlore-rich target. It was found that the growth conditions required to produce almost 100% perovskite Pb(Mg1/3Nb2/3)O3 (PMN) films were largely independent of target crystallography. Films were characterized crystallographically using x-ray diffraction and plan view transmission electron microscopy, chemically using energy dispersive x-ray analysis, and electrically by fabricating a planar thin film capacitor structure and monitoring capacitance as a function of temperature. All characterization techniques indicated that perovskite PMN thin films had been successfully fabricated.

Control of composition and structure of ferroelectric oxide thin films grown by pulsed laser deposition

2008 ◽  
Vol 5 (10) ◽  
pp. 3293-3297 ◽  
Author(s):  
Maryline Guilloux-Viry ◽  
Wei Peng ◽  
Stéphanie Députier ◽  
Valérie Bouquet ◽  
André Perrin
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Oxide Thin Films ◽  
Composition And Structure ◽  
Ferroelectric Oxide

scholarly journals Epitaxial growth of β-Ga2O3 thin films on Ga2O3 and Al2O3 substrates by using pulsed laser deposition

2019 ◽  
Vol 09 (04) ◽  
pp. 1950032 ◽  
Author(s):  
Yuxin An ◽  
Liyan Dai ◽  
Ying Wu ◽  
Biao Wu ◽  
Yanfei Zhao ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Optical Transmittance ◽  
Laser Deposition ◽  
Ultraviolet Region ◽  
X Ray Diffraction ◽  
Chemical Cleaning ◽  
Transmission Electron ◽  
Xrd Patterns

In this work, we have successfully grown high quality epitaxial [Formula: see text]-Ga2O3 thin films on [Formula: see text]-Ga2O3 (100) and Al2O3(0001) substrates using pulsed laser deposition (PLD). By optimizing temperature and oxygen pressure, the best conditions were found to be 650–700∘C and 0.5[Formula: see text]Pa. To further improve the quality of hetero-epitaxial [Formula: see text]-Ga2O3, the sapphire substrates were pretreated for atomic terraced surface by chemical cleaning and high temperature annealing. From the optical transmittance measurements, the films grown at 600–750∘C exhibit a clear absorption edge at deep ultraviolet region around 250–275[Formula: see text]nm wavelength. High resolution transmission electron microscope (HRTEM) images and X-ray diffraction (XRD) patterns demonstrate that [Formula: see text]-Ga2O3(-201)//Al2O3(0001) epitaxial texture dominated the epitaxial oxide films on sapphire substrate, which opens up the possibilities of high power electric devices.

Germanium Nanostructures Fabricated by PLD

1998 ◽  
Vol 536 ◽  
Author(s):  
K. M. Hassan ◽  
A. K. Sharma ◽  
J. Narayan ◽  
J. F. Muth ◽  
C. W. Teng
Keyword(s):  
Pulsed Laser Deposition ◽  
Electronic Transport ◽  
Pulsed Laser ◽  
Single Layer ◽  
Laser Deposition ◽  
Transmission Electron ◽  
The Matrix ◽  
Average Size ◽  
Substrate Temperatures

AbstractQuantum confined nanostructures of semiconductors such as Ge and Si are being actively studied due to their interesting optical and electronic transport properties. We fabricated Ge nanostructures buried in the matrix of polycrystalline-AIN grown on Si(111) by pulsed laser deposition at lower substrate temperatures than that used in previous studies. The characterization of these structures was performed using high resolution transmission electron microscopy (HRTEM), photoluminescence and Raman spectroscopy. HRTEM observations show that the Ge islands are single crystal with a pyramidal shape. The average size of Ge islands was determined to be 15 nm, considerably smaller than that produced by other techniques. The Raman spectrum reveals a peak downward shift, upto 295 cm−1, of the Ge-Ge mode caused by quantum confinement in the Ge-dots. Photoluminescence (PL) was observed both with a single layer of Ge nanodots embedded in the AlN matrix and from ten layers of dots interspersed with AIN. The PL of the dots was blue shifted by ˜0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ˜1.0 eV. The full width at half maximum (FWHM) of the peak was 13 meV, for the single layer and 8 meV for the ten layered sample, indicating that the Ge nanodots are fairly uniform in size, which was found to be consistent with our HRTEM results. The importance of pulsed laser deposition (PLD) in fabricating novel nanostructures is discussed.

A Simple and Effective Route to Annihilate Defects in Nanocrystalline SnO2 Thin Films Prepared by Pulsed Laser Deposition

2007 ◽  
Vol 1026 ◽  
Author(s):  
Zhiwen Chen ◽  
C. M. L. Wu ◽  
C. H. Shek ◽  
J. K. L. Lai ◽  
Z. Jiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Pulsed Laser Deposition ◽  
Gas Sensors ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Sno2 Thin Films

AbstractThe microstructural defects of nanocrystalline SnO2 thin films prepared by pulsed laser deposition have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. Defects inside nanocrystalline SnO2 thin films could be significantly reduced by annealing the SnO2 thin films at 300 °C for 2 h. High-resolution transmission electron microscopy showed that stacking faults and twins were annihilated upon annealing. In particular, the edges of the SnO2 nanoparticles demonstrated perfect lattices free of defects after annealing. Raman spectra also confirmed that annealing the specimen was almost defect-free. By using thermal annealing, defect-free nanocrystalline SnO2 thin films can be prepared in a simple and practical way, which holds promise for applications as transparent electrodes and solid-state gas sensors.

Synthesis and Characterization of Metal-Ceramic Thin Film Nanocomposites With Improved Mechanical Properties

2002 ◽  
Author(s):  
D. Kumar ◽  
N. Sudhir ◽  
S. Yarmolenko ◽  
Q. Wei ◽  
J. Sankar ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Thin Film Composites ◽  
Film Composites

Thin films composite materials consisting of metallic nanocrystals embedded in an insulator host have been synthesized using alternating-target pulsed laser deposition of Fe/Ni and Al2O3. The evaluation of structural quality of the thin film composites using high resolution transmission electron microscopy and scanning transmission electron microscopy with atomic number contrast has revealed the formation of a biphase system with thermodynamically driven segregation of Ni and alumina during pulsed laser deposition. The best hardness values of the thin film composites, measured using nanoindentation techniques, was found to 20–30% larger than pure alumina films fabricated under identical conditions. The improvement in values of hardness of Al2O3 thin films by embedding metal nanocrystals is related to the evolution of a microstructure which efficiently hinders the manipulation and movement of dislocation and the growth of microcracks, which in turn, is achieved by grain boundary hardening.

Substrate temperature dependence of structure and resistivity of SrRuO3 thin films grown by pulsed laser deposition on (100) SrTiO3

1999 ◽  
Vol 14 (11) ◽  
pp. 4385-4394 ◽  
Author(s):  
N. D. Zakharov ◽  
K. M. Satyalakshmi ◽  
G. Koren ◽  
D. Hesse
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Cubic Phase ◽  
Orthorhombic Structure ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Different Temperatures

The resistivity of SrRuO3 thin films on (001) SrTiO3 substrates grown at different temperatures by pulsed laser deposition is correlated to the microstructure. Films grown at 775 °C are of an orthorhombic structure, contain very few defects, and exhibit a low resistivity of 150 μΩ cm. Films grown at other temperatures contain a cubic phase and show higher resistivities. The defects present in the films, particularly twins and antiphase boundaries, are analyzed by high-resolution transmission electron microscopy, and their origin, as well as influence on film resistivity, is discussed.

The Morphology of Polytetrafluoroethylene (PTFE) Thin Films Formed by Pulsed-Laser Deposition

1995 ◽  
Vol 385 ◽  
Author(s):  
M. Grant Norton ◽  
Wenbiao Jiang ◽  
J. Thomas Dickinson
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Interface Plane ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Film Substrate ◽  
Substrate Temperatures

ABSTRACTThin films of polytetrafluoroethylene have been formed by the pulsed-laser deposition technique. The structure of the films was found to be dependent upon the substrate temperature during deposition. At substrate temperatures from room temperature to 200°C the films were determined, by transmission electron microscopy and X-ray diffraction techniques, to be amorphous. Films formed at higher substrate temperatures were found to contain both amorphous and crystalline components. The data for the crystalline component is consistent with it being highly ordered with the long helical molecular chains aligned parallel to the film-substrate interface plane. The maximum amount of crystalline material occurred when the substrate temperature was close to the melting temperature of the polymer.

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