Plasma Dynamics During Pulsed Laser Evaporation of High Tc Superconductors

1990 ◽  
Vol 201 ◽  
Author(s):  
Rajiv K. Singh ◽  
R. Neifeld ◽  
J. Narayan
Keyword(s):  
Theoretical Model ◽  
Energy Density ◽  
Excimer Laser ◽  
Pulsed Laser ◽  
Laser Wavelength ◽  
Laser Evaporation ◽  
Degree Of Ionization ◽  
Plasma Dynamics ◽  
Excimer Laser Irradiation

AbstractWe have theoretically and experimentally investigated the dynamics of the evaporated material generated by nanosecond excimer laser irradiation of YBa2Cu3O7 targets in vacuum. The velocity distribution and the ionization of the plasma were determined by the ion time of flight measurements. The excimer laser ablated species possessed very high velocities (> 106 cm/sec) which increased non-linearly with energy density. The ionization/ volume of the evaporated material exhibited a weak dependence on energy density, thereby suggesting the role of nonthermal mechanisms in the ionization process. These experimental results have been correlated with the theoretical model analyzing the plasma dynamics during pulsed laser evaporation of materials. A new modification to the earlier theoretical model is developed which accurately predicts the terminal velocities and the effect of ionization on these velocities. Various factors including, evaporation rates, degree of ionization, and laser wavelength which affect the plasma velocities will also be discussed.

Pulsed Excimer Laser Processing of AlN/GaN Thin Films

1996 ◽  
Vol 449 ◽  
Author(s):  
W. S. Wong ◽  
L. F. Schloss ◽  
G.S. Sudhir ◽  
B. P. Linder ◽  
K-M. Yu ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Excimer Laser ◽  
Laser Processing ◽  
Laser Annealing ◽  
Rutherford Backscattering Spectrometry ◽  
Pulsed Laser ◽  
Emission Peak ◽  
Dopant Activation ◽  
Pulsed Laser Annealing

ABSTRACTA KrF (248 nm) excimer laser with a 38 ns pulse width was used to study pulsed laser annealing of AIN/GaN bi-layers and dopant activation of Mg-implanted GaN thin films. For the AIN/GaN bi-layers, cathodoluminescence (CL) showed an increase in the intensity of the GaN band-edge peak at 3.47 eV after pulsed laser annealing at an energy density of 2000 mJ/cm2. Rutherford backscattering spectrometry of a Mg-implanted A1N (75 nm thick)/GaN (1.0 μm thick) thin-film heterostructure showed a 20% reduction of the 4He+ backscattering yield after laser annealing at an energy density of 400 mJ/cm2. CL measurements revealed a 410 nm emission peak indicating the incorporation of Mg after laser processing.

The Origin and Implications of (111)-Textured Grains Obtained via Nucleation and Growth of Solids in Pulsed-Laser-Quenched Al Films on SiO2

2006 ◽  
Vol 979 ◽  
Author(s):  
J. B. Choi ◽  
Min H. Choi ◽  
U.-J. Chung ◽  
A. B. Limanov ◽  
James S. Im
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Heterogeneous Nucleation ◽  
Microstructural Analysis ◽  
Pulsed Laser ◽  
Nucleation And Growth ◽  
Nucleation Model ◽  
Wide Energy ◽  
Excimer Laser Irradiation ◽  
Condensed Systems

AbstractWe have investigated excimer laser irradiation of 2000-Å-thin as-deposited Al films on SiO2. Microstructural analysis of the irradiated films conducted with AFM and EBSD techniques reveals that there exists a wide energy density interval over which large equaxed grains with a strong (111) texture are obtained. Based on thermal, transformational, and microstructural considerations, we propose a heterogeneous nucleation model to account for the observed behaviors, and discuss the implication of the model on the phenomenon of heterogeneous nucleation of crystalline solids in condensed systems as regards the thermodynamic role played by the orientation of subcritical clusters.

Amorphous Gallium Produced By Pulsed Excimer Laser Irradiation

1985 ◽  
Vol 51 ◽  
Author(s):  
J. Fröhlingsdorf ◽  
B. Stritzker
Keyword(s):  
Transition Temperature ◽  
Energy Density ◽  
Excimer Laser ◽  
Low Temperatures ◽  
Threshold Energy ◽  
Residual Resistivity ◽  
Superconducting Transition ◽  
Β Phase ◽  
Excimer Laser Irradiation ◽  
Vapor Quenching

ABSTRACTPure crystalline Ga films (α-Ga, β-Ga) have been irradiated at low temperatures (≤ 20 K) with an Excimer laser. By measuring the superconducting transition temperature Tc and the residual resistivity ≤o, the resulting Ga phases (α-Ga, β-Ga, a-Ga) can be identified.Both crystalline Ga phases can be transformed into the amorphous phase.The threshold energy density for the β→ a transition depends on the film thickness, whereas the α →. a transition occurs always at about 225 mJ/cm2 This behavior is in agreement with earlier observations that a-Ga can grow on top of the in-phase but not on the β-phase.The results of laser quenching are compared with other non-equilibrium techniques for the production of a-Ga, such as vapor quenching and low temperature ion iradiation.

Matrix-Assisted Pulsed Laser Evaporation Deposition of Pd Nanoparticles: The Role of Solvent

2015 ◽  
Vol 7 (11) ◽  
pp. 2388-2400
Author(s):  
Maura Cesaria ◽  
Anna Paola Caricato ◽  
Antonietta Taurino ◽  
Vincenzo Resta ◽  
Maria Rosaria Belviso ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Pd Nanoparticles ◽  
Laser Evaporation ◽  
Role Of Solvent

The Role of Hydrogen in Laser Deposition of Diamond-Like Carbon

1991 ◽  
Vol 236 ◽  
Author(s):  
D. Thebert-Peeler ◽  
P.T. Murray ◽  
L. Petry ◽  
T.W. Haas
Keyword(s):  
Pulsed Laser ◽  
Laser Deposition ◽  
Laser Evaporation ◽  
Diamond Like Carbon ◽  
Ablation Process ◽  
Laser Ablation Process ◽  
Ir Laser ◽  
Temperature Deposition ◽  
Energy Incident

AbstractThin films have been grown on Si (100) substrates by pulsed laser evaporation of graphite using both IR and UV radiation. The character of the resulting film is found to be independent of the presence of H°. Diamond-like films are found to be a result of low (RT) temperature deposition of the higher energy incident particles of the UV (versus IR) laser ablation process.

The Role of the Energy Density in Pulsed Laser Deposition of Bioactive Glass Films

2013 ◽  
Vol 631-632 ◽  
pp. 90-94
Author(s):  
Ya Fan Zhao ◽  
Ming Da Song
Keyword(s):  
Energy Density ◽  
Deposition Rate ◽  
Film Growth ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Glass ◽  
Lower Energy Density ◽  
Density Threshold

Effect of the energy density on the composition, morphology and deposition rate of the bioglass thin films deposited by pulsed laser was studied by energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and crystal lattice monitor. There is slight compositional difference between the film and the target at lower energy density. Morphology of the films is compact with the particles on the surface of them. Structure of the films is amorphous glass and the size of the particles increases with the energy density. Deposition rate increases with the energy density and the energy density threshold of the film growth is about 2.5J/cm2.

The Role of Hydrogen in Laser Deposition of Diamond-Like Carbon

1991 ◽  
Vol 235 ◽  
Author(s):  
D. Thebert-Peeler ◽  
P. T. Murray ◽  
L. Petry ◽  
T. W. Haas
Keyword(s):  
Pulsed Laser ◽  
Laser Deposition ◽  
Laser Evaporation ◽  
Diamond Like Carbon ◽  
Ablation Process ◽  
Laser Ablation Process ◽  
Ir Laser ◽  
Temperature Deposition ◽  
Energy Incident

ABSTRACTThin films have been grown on Si (100) substrates by pulsed laser evaporation of graphite using both IR and UV radiation. The character of the resulting film is found to be independent of the presence of H°. Diamond-like films are found to be a result of low (RT) temperature deposition of the higher energy incident particles of the UV (versus IR) laser ablation process.

Sign in / Sign up

Export Citation Format

Share Document