Modeling for Chemical-Etching Enhanced Pulsed Laser Ablation

2019 ◽  
Author(s):  
Xing Zhang ◽  
Bo Mao ◽  
Rebecca Histed ◽  
Yiliang Liao
Keyword(s):  
Laser Ablation ◽  
Chemical Etching ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Ablation Rate ◽  
Temperature Dependent ◽  
Laser Shock Processing ◽  
Active Liquid ◽  
Shock Processing

Abstract Pulsed laser ablation (PLA) under active liquid confinement, also known as chemical etching enhanced pulsed laser ablation (CE-PLA), has emerged as a novel laser processing methodology, which breaks the current major limitation in underwater PLA caused by the breakdown plasma and effectively improves the efficiencies of underwater PLA-based processes, such as laser-assisted nano-/micro-machining and laser shock processing. Despite of experimental efforts, little attention has been paid on CE-PLA process modeling. In this study, an extended two-temperature model is proposed to predict the temporal/spatial evolution of the electron-lattice temperature and the ablation rate in the CE-PLA process. The model is developed with considerations on the temperature-dependent electronic thermal properties and optical properties of the target material. The ablation rate is formulated by incorporating the mutual promotion between ablation and etching processes. The simulation results are validated by the experimental data of CE-PLA of zinc under the liquid confinement of hydrogen peroxide.

Early stages of the growth of BaTiO3 thin films studied by Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 706-707
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
Christopher Scarfone ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Room Temperature ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Cubic Phase ◽  
Transmission Electron ◽  
Tetragonal Form

Barium titanate (BaTiO3) may be used in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. In particular, the tetragonal form of BaTiO3, which is stable at room temperature, exhibits ferro-, pyro- and piezoelectric properties. It is desirable to form films of the tetragonal phase directly and thus to avoid formation of either amorphous or polycrystalline material or to form material of the non-ferroelectric cubic phase. Recently two techniques, pulsed-laser ablation and reactive evaporation, have been used to form BaTiO3 thin-films. In the present study BaTiO3 thin-films have been formed using the pulsed-laser ablation technique. Pulsed-laser ablation is now widely used to produce thin-films of the high temperature superconductors and has many advantages over other techniques, in particular the formation of films which maintain the stoichiometry of the target material and by controlling the processing conditions the formation of films having defined crystalline phases.

Growth of Epitaxial ZnS Films by Pulsed-Laser Ablation

1992 ◽  
Vol 242 ◽  
Author(s):  
J. W. McCamy ◽  
D. H. Lowndes ◽  
J. D. Budai ◽  
B. C. Chakoumakos ◽  
R. A. Zuhr
Keyword(s):  
Laser Ablation ◽  
Stacking Faults ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Temperature Dependent ◽  
High Quality ◽  
X Ray ◽  
Fault Density ◽  
Highly Uniform ◽  
Zns Films

ABSTRACTPulsed KrF (248nm) laser ablation of a polycrystailine ZnS target has been used to grow high quality, carbon-free, epitaxial ZnS thin films on GaAs(OOl), GaAs(111), and GaP(OOl). The films were grown at temperatures of 150–450°C, using a rotating substrate heater and deposition geometry that produces films with highly uniform thickness. X-ray rocking curves are consistent with (111) stacking faults being the dominant defects in the ZnS films grown on GaAs. The estimated stacking fault density is ∼6 × 1010 cm-3, comparable to the best MOCVD ZnS films. RBS analysis shows that these defects are located predominantly near the GaAs-ZnS interface. The anisotropy of the ZnS growth rate, between the GaAs(001) and GaAs(111) surfaces, was found to be temperature-dependent.

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.

EFFECT OF LASER WAVELENGTH AND ABLATION TIME ON PULSED LASER ABLATION SYNTHESIS OF AL NANOPARTICLES IN ETHANOL

2012 ◽  
Vol 05 ◽  
pp. 58-65 ◽  
Author(s):  
A. BALADI ◽  
R. SARRAF MAMOORY
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Ablation Rate ◽  
Laser Wavelength ◽  
Aluminum Nanoparticles ◽  
Ablation Efficiency ◽  
Ablation Time ◽  
Al Nanoparticles ◽  
Ablated Mass

Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol for 5-15 minutes using the 1064 and 533 nm wavelengths of a Nd:YAG laser with energies of 280-320 mJ per pulse. It has been found that higher wavelength leads to significantly higher ablation efficiency, and finer spherical nanoparticles are also synthesized. Besides, it was obvious that higher ablation time resulted in higher ablated mass, while lower ablation rate was observed. Finer nanoparticles, moreover, are synthesized in higher ablation times.

Laser‐beam deflection measurements and modeling of pulsed laser ablation rate and near‐surface plume densities in vacuum

1991 ◽  
Vol 70 (2) ◽  
pp. 587-593 ◽  
Author(s):  
Peter L. G. Ventzek ◽  
Ronald M. Gilgenbach ◽  
David M. Heffelfinger ◽  
Jeffrey A. Sell
Keyword(s):  
Laser Ablation ◽  
Laser Beam ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Ablation Rate ◽  
Beam Deflection ◽  
Near Surface

Temperature Dependent Up-Conversion Luminescence Properties of Er3+ Doped KNN Ultrafine Powders Prepared by Pulsed Laser Ablation in Liquid

2020 ◽  
Vol 998 ◽  
pp. 197-202
Author(s):  
Zhen Liu ◽  
Di Hu Chen
Keyword(s):  
Electron Microscopy ◽  
Laser Ablation ◽  
Emission Intensity ◽  
Energy Levels ◽  
Pulsed Laser ◽  
Green Emission ◽  
Pulsed Laser Ablation ◽  
Temperature Sensing ◽  
Ultrafine Powders ◽  
Temperature Dependent

Er3+ doped potassium sodium niobate (KNN: Er) ultrafine powders have been prepared by pulsed laser ablation in water. X-ray diffraction (XRD) pattern of the sample demonstrated that the as-synthesized powders were crystalized in orthorhombic phase. Scanning electron microscopy (SEM) and transmittance electron microscopy (TEM) images exhibited that the morphology of ultrafine powders are cube-like. Under the excitation of 980 nm laser, the sample exhibits green emission, which is originated from the transition of thermal coupled energy levels (2H11/2, 4S3/2) to ground state level 4I15/2. Temperature dependent up-conversion emission intensity associated with thermal quenching of total green emission band and the fluorescence intensity ratio (FIR) between two sub-emission bands related to population of thermal coupled energy levels are investigated for temperature sensing in the temperature range of 300 K to 480 K. The temperature sensing performances related to different technique were discussed. A maximum relative sensitivity reaches 1.01% K-1 at 464 K for emission intensity thermometry and that is 0.84% K-1 at 374 K for FIR thermometry technique. All these results show that KNN: Er ultrafine phosphors prepared via pulsed laser ablation in water have prospect for non-contact temperature sensing.

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