Excimer Laser Ablation of Silicon at High Temperature

1998 ◽  
Vol 526 ◽  
Author(s):  
Y.F. Zhang ◽  
Y.H. Tang ◽  
C. S. Lee ◽  
N. Wang ◽  
I. Bello ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Laser Beam ◽  
Pulsed Laser ◽  
Target Surface ◽  
Si Nanowires ◽  
Beam Direction ◽  
Excimer Laser Ablation ◽  
Deep Channel ◽  
Porous Skeleton ◽  
Si Nanostructures

AbstractPulsed laser ablation of granulated Si target was carried out at 1200 °C in an Ar atmosphere. Multishot ablated target surface forms intensity dependent features, including porous, skeleton, and columnar structures. Very long columnar structures were observed when the angle of the target surface with respect to the direction of the laser beam was small. Evidence on preferable remove of smaller particles has been observed. Formation of the columnar structures started from the biggest particles at the surface and grew deeper, straight in the laser beam direction, by consuming the removed Si species from the deep channel between columns. The Si species ablated off the granulated Si target deposited as Si nanowires or nanoparticles down stream of the Ar flow. Significant decrease in the deposition rate of Si nanostructures has been observed upon the formation of the columnar structures at the target surface.

Preferential Crystallization of β-FeSi2 from Micro-droplets Generated by Laser Ablation.

2004 ◽  
Vol 848 ◽  
Author(s):  
Aiko Narazaki ◽  
Tadatake Sato ◽  
Yoshizo Kawaguchi ◽  
Hiroyuki Niino
Keyword(s):  
Laser Ablation ◽  
Room Temperature ◽  
Crystallization Behavior ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Excimer Laser Ablation ◽  
Pulsed Laser Annealing ◽  
Molten Droplets ◽  
Equilibrium Process ◽  
Krf Excimer Laser

ABSTRACTβ-FeSi2 was successfully fabricated at room temperature via the deposition of molten micro-droplets generated by the KrF excimer laser ablation. Only the molten droplets precipitated as the β-FeSi2 crystalline phase on a silicon substrate kept even at room temperature, whereas the rest of film was amorphous. The crystallization behavior of micro-droplets has been discussed in the light of non-equilibrium process due to rapid cooling on the substrate. After the deposition, pulsed laser annealing was also performed in order to improve the crystallinity of the β-FeSi2 microprecipitates-containing film.

Effect of the dynamic absorptance of a metallic target surface on pulsed laser ablation

2006 ◽  
Vol 203 (5) ◽  
pp. 906-918 ◽  
Author(s):  
Li Li ◽  
Duanming Zhang ◽  
Zhihua Li ◽  
Li Guan ◽  
Xinyu Tan ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Target Surface ◽  
Pulsed Laser Ablation ◽  
Metallic Target

Pulsed Laser Ablation as a Source of Energetic Reactants: Synthesis of Superconducting High to Thin Films

1990 ◽  
Vol 191 ◽  
Author(s):  
L. Lynds ◽  
B. R. Weinberger
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Mass Range ◽  
Squid Magnetometry ◽  
Atomic Ions ◽  
Excimer Laser Ablation ◽  
Multiply Charged ◽  
Ion Energies ◽  
Cu Ions ◽  
Angular Energy

ABSTRACTPulsed KrF (248 nm) excimer laser ablation of targets can provide a source of atomic particles with energies in the range of 40 – 850 eV with beam-like characteristics. Optical intensities above about 109 W/cm2 lead mainly to single and multiply charged ground state positive atomic ions plus electrons with a pronounced angular energy dependence, the highest energies peaked in the direction normal to the target. A wide mass range of metallic and non-metallic targets were studied to determine the effects of atomic weights and other physical properties on the distribution of ion energies. Analysis of the energetics indicates that ablation mechanisms are non-equilibrium in nature. We have explored the use of very energetic (200–400 eV) Y, Ba and Cu ions to form very thin YBa2Cu3O7-x superconducting films grown on flat gold surfaces. SQUID magnetometry is used to study the temperature and field dependence of magnetization in these materials.

SYNTHESIS OF ULTRAFINE/NANOSIZE POWDERS OF IRON OXIDES BY PULSED LASER ABLATION AND COLD CONDENSATION

1996 ◽  
Vol 10 (30) ◽  
pp. 1517-1527 ◽  
Author(s):  
S. R. SHINDE ◽  
A. G. BANPURKAR ◽  
K. P. ADHI ◽  
A. V. LIMAYE ◽  
S. B. OGALE ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excimer Laser Ablation ◽  
Nanosize Particles ◽  
Cold Condensation ◽  
Scanning Electron

Ultrafine/nanosize powders of iron oxide have been synthesized from a sintered α- Fe 2 O 3 target by pulsed excimer laser ablation and cold condensation. The influence of target porosity and temperature of condensation on the formation of nanosize particles has been studied. The nanosize powders have been characterized by X-ray diffraction, Mössbauer spectroscopy, vibrating sample magnetometry and scanning electron microscopy. It is shown that the formation of ultrafine/nanosize particles is strongly governed by the target porosity, whereas, the temperature of condensation, over a range from 27°C to −130°C, does not affect the magnetic properties of the nanoparticles.

Does the Subsurface Superheating Effect Really Exist?

1998 ◽  
Vol 526 ◽  
Author(s):  
Valentin Craciun ◽  
Doina Craciun
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Target Material ◽  
Target Surface ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Gas Release ◽  
Actual Mechanism ◽  
Emission Volume ◽  
Modification Of The Surface

AbstractThe existence inside targets during pulsed laser ablation of a sub-surface superheating effect (SSSH) has been predicted by numerical temperature estimations. The experimental evidence has been so far only indirect, based on the modification of the surface morphology caused by the explosive volume boiling induced by the SSSH effect. However, round-shaped micrometer-sized cavities formed by gas release due to volume boiling have been found on several target materials even when the temperature estimations did not predict any SSSH effect. Although the SSSH effect could exist under certain conditions, it seems that it is not a prerequisite for explosive volume boiling which is the actual mechanism responsible for droplets emission. Volume boiling could occur whenever a thick liquid layer, whose temperature is much higher than the equilibrium boiling value is formed and lasts for several tens of nanoseconds on the target surface, a situation usually found when the laser wavelength is poorly absorbed by the target material.

scholarly journals Role of confining liquids on the properties of Cu@Cu2O nanoparticles synthesized by pulsed laser ablation and a correlative ablation study of the target surface

RSC Advances ◽  
2019 ◽  
Vol 9 (26) ◽  
pp. 15124-15139 ◽  
Author(s):  
Prahlad K. Baruah ◽  
Ashwini K. Sharma ◽  
Alika Khare
Keyword(s):  
Laser Ablation ◽  
Organic Solvents ◽  
Pulsed Laser ◽  
Target Surface ◽  
Pulsed Laser Ablation ◽  
Cu Nanoparticles ◽  
Cu2o Nanoparticles ◽  
Ablation Study

Formation of insufficiently oxidized Cu nanoparticles by laser ablation in organic solvents is correlated with the ablation of the target surface.

Effects of Excimer Laser Ablation on the Surface of Hexagonal Boron Nitride

1990 ◽  
Vol 201 ◽  
Author(s):  
G. L. Doll ◽  
T. A. Perry ◽  
J. A. Sell
Keyword(s):  
Laser Ablation ◽  
Boron Nitride ◽  
Gas Phase ◽  
Hexagonal Boron Nitride ◽  
Cubic Boron Nitride ◽  
Pulsed Laser ◽  
Excimer Laser Ablation ◽  
Induced Changes ◽  
Boron Nitride Films ◽  
Morphology Changes

AbstractThe laser-induced changes in the hexagonal boron nitride targets that are used in the deposition of pulsed laser-deposited cubic boron nitride films are examined. Although the structure of the hexagonal boron nitride in the irradiated areas is unaltered, the surface morphology changes considerably. Boron-rich spheroids were found to cover the irradiated area. Their origin is consistent with the hydrodynamic sputtering of the hexagonal boron nitride targets, and a liberation of nitrogen atoms to the gas phase.

PULSED LASER DEPOSITION — ABLATION MECHANISM AND APPLICATIONS

2013 ◽  
Vol 22 ◽  
pp. 355-360 ◽  
Author(s):  
M. C. RAO
Keyword(s):  
High Temperature ◽  
Laser Ablation ◽  
Laser Beam ◽  
Pulsed Laser Deposition ◽  
Continuous Wave ◽  
High Temperature Superconductivity ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Wide Range ◽  
Laser Flux

Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma. Usually, laser ablation refers to removing material with a pulsed laser, but it is possible to ablate material with a continuous wave laser beam if the laser intensity is high enough. In general, the method of pulsed laser deposition (PLD) is simple. Only few parameters need to be controlled during the process. Targets used in PLD are small compared with other targets used in other sputtering techniques. It is quite easy to produce multi-layer film composed of two or more materials. Besides, by controlling the number of pulses, a fine control of film thickness can be achieved. Pulsed-laser deposition has been used to deposit an extraordinarily wide range of materials. Historically, the most significant application of PLD has been in the area of high temperature superconducting thin films. The demonstration that PLD could be used to deposit YBa2Cu3O7-x (YBCO) films with zero resistivity at nearly 85 K sparked a significant amount of high temperature superconductivity research over the past decade and has stimulated research in PLD in general. The most striking limitations of PLD are the generation of particulates during the deposition process and the non uniform coating thickness, when substrates of large area are deposited.

Numerical Modeling of Laser Ablation of Polymers and Metals by Nanosecond Pulses of Infrared Radiation

2010 ◽  
Vol 5 (1) ◽  
pp. 37-47
Author(s):  
Lev A. Zakharov ◽  
Nadezhda M. Bulgakova
Keyword(s):  
Numerical Modeling ◽  
Laser Ablation ◽  
Initial Temperature ◽  
Pulsed Laser ◽  
Target Surface ◽  
Laser Pulses ◽  
Ablation Depth ◽  
Metallic Materials ◽  
Nanosecond Pulses ◽  
Vaporization Process

In the paper a comparative analysis has been carried out of pulsed laser ablation of polymers and metals. On the basis of a thermal model with the mobile boundary «vapor – target surface», numerical modeling of laser ablation of poly(methyl methacrylate) and copper by nanosecond CO2 laser pulses (at wavelength of 10.6 nm) has been performed for different initial temperatures of the irradiated samples. Conclusions are drawn on differences in heating and ablation dynamics of polymer and metallic materials, values of subsurface superheating, and initial temperature effects on the vaporization process and ablation depth.

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