Evidence for the physical basis and universality of the elimination of particulates using dual-laser ablation. I. Dynamic time-resolved target melt studies, and film growth of Y2O3 and ZnO

2002 ◽  
Vol 91 (4) ◽  
pp. 1828-1836 ◽  
Author(s):  
Pritish Mukherjee ◽  
Shudong Chen ◽  
John B. Cuff ◽  
Palanikumaran Sakthivel ◽  
Sarath Witanachchi
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Physical Basis ◽  
Time Resolved ◽  
Dynamic Time ◽  
Dual Laser

scholarly journals Ag nanocluster synthesis by laser ablation in Ar atmosphere: A plume dynamics analysis

2009 ◽  
Vol 27 (2) ◽  
pp. 281-290 ◽  
Author(s):  
E. Fazio ◽  
F. Neri ◽  
P.M. Ossi ◽  
N. Santo ◽  
S. Trusso
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Deposition Process ◽  
Morphological Properties ◽  
Plasma Expansion ◽  
Plasma Confinement ◽  
Time Resolved ◽  
Transmission Electron ◽  
Ambient Gas ◽  
Photography Analysis

AbstractAg thin films were deposited by pulsed laser ablation in a controlled Ar atmosphere. The deposition process was performed at different Ar pressure values in the range between 10 and 100 Pa to investigate the influence of ambient gas pressure on the plasma expansion dynamics and on the film structural properties. Position, velocity and volume of the laser generated plasma as functions of time were obtained by time resolved fast photography. The morphological properties of the films were investigated by transmission electron microscopy which shows that film growth proceeds via aggregation on the substrates of nanoclusters formedin the expandingplume. The formation of nanoparticles takes place as a consequence of plasma confinement induced by the interaction with ambient gas species. Data from fast photography analysis were used as input parameters to calculate the size of the nanoparticles using a model that takes into account the collisional nature of the laser generated silver plasma.

scholarly journals Highly Ionized Carbon Plasma Generation by Dual-Laser Ablation for Diamond-Like Carbon Film Growth

2000 ◽  
Vol 617 ◽  
Author(s):  
S. Witanachchi ◽  
A. M. Miyawa ◽  
P. Mukherjee
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Carbon Film ◽  
Plasma Temperature ◽  
Optical Emission ◽  
Carbon Films ◽  
Rapid Expansion ◽  
Laser Ablation Process ◽  
Carbon Plasma ◽  
Dual Laser

AbstractCarbon plasmas produced by excimer laser ablation show a low ionization yield of about 8-10%. The coupling of a second CO2laser pulse into the plasma in the dual-laser ablation process significantly increases the plasma temperature and the ionization. The resulting rapid expansion of the plasma gives rise to high ion kinetic energies and broader ion expansion profiles [1]. Optical emission spectroscopy and an ion probe have been used to investigate the dynamics of the carbon plasma. Single and dual-laser ablated carbon plumes have been deposited on DC-biased silicon substrates to form amorphous carbon films. The diamond-like behavior of these films was studied by Raman spectroscopy. The Raman spectra were deconvolved to gauge the effect of the density and the energy of ions on the formation of diamond-like sp3 -bonded carbon (DLC) films. The advantage offered by the dual-laser process for the growth of DLC films is discussed.

Dual‐laser ablation for particulate‐free film growth

1995 ◽  
Vol 66 (12) ◽  
pp. 1469-1471 ◽  
Author(s):  
S. Witanachchi ◽  
K. Ahmed ◽  
P. Sakthivel ◽  
P. Mukherjee
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Free Film ◽  
Dual Laser

Time-resolved measurements of sodium emission in the plume generated by laser ablation of myocardium tissue

2004 ◽  
Author(s):  
Hanriete P. de Souza ◽  
Egberto Munin ◽  
Carlos Eduardo de Vilhena Paiva ◽  
Leandro P. Alves ◽  
Marcela L. Redigolo ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Time Resolved ◽  
Time Resolved Measurements

Time-resolved Photoconductivity as a Probe of Carrier Transport in Microcrystalline Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Steve Reynolds
Keyword(s):  
Density Of States ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Film Growth ◽  
Hole Mobility ◽  
Transport Parameters ◽  
Microcrystalline Silicon ◽  
Time Resolved ◽  
Transient Photoconductivity ◽  
Transport Measurements

AbstractThe use of transient photoconductivity techniques in the investigation of carrier transport in microcrystalline silicon is described. Results are presented which highlight variations in transport parameters such as carrier mobility and density of states with structure composition. Hole mobility is significantly enhanced by crystalline content in the film of 10% or less. The density of states inferred from transport measurements parallel to and at right angles to the direction of film growth differ somewhat, suggesting that transport may be anisotropic.

Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film

2011 ◽  
Vol 1305 ◽  
Author(s):  
Ikurou Umezu ◽  
Shunto Okubo ◽  
Akira Sugimura
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
Spatial Confinement ◽  
The Individual ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTThe Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes during pulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure.

scholarly journals Time-Resolved Quadrupole Mass Spectrometric Studies on Pulsed Laser Ablation of TiO2

1999 ◽  
Vol 18 (3) ◽  
pp. 99-109 ◽  
Author(s):  
Yongxin Tang ◽  
Zhenhui Han ◽  
Qizong Qin
Keyword(s):  
Laser Ablation ◽  
Continuous Wave ◽  
Center Of Mass ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Ionic Species ◽  
Mass Spectrometric ◽  
Quadrupole Mass ◽  
Time Resolved ◽  
Ambient Oxygen

Pulsed laser ablation of TiO2 at 355 nm and 532 nm has been investigated using an angleand time-resolved quadrupole mass spectrometric technique. The major ablated species include O (m/e = 16), O2 (m/e = 32), Ti (m/e = 48), TiO (m/e = 64) and TiO2 (m/e = 80). The time-of-flight (TOF) spectra of ablated species are measured for the ionic and neutral ablated species, and they can be fitted by a Maxwell – Boltzmann (M – B) distribution with a center-of-mass velocity. The measured angular distributions of the ionic species (O+ and Ti+) and the neutral species (O and Ti) can be fitted with cos⁡nθ and a cos⁡θ + (1−a)cos⁡nθ, respectively. In addition, a continuous wave oxygen molecular beam is introduced into the ablated plume, and the enhancement of the signal intensities of TiO is observed. It implies that the ablated Ti atoms/ions species can react with ambient oxygen molecules in the gas phase. In the meanwhile, the physicochemical mechanism of pulsed laser ablation of TiO2 is discussed.

Time-resolved electron imaging of femtosecond laser ablation

2005 ◽  
pp. 825-827
Author(s):  
Yasuaki Okano ◽  
Yoichiro Hironaka ◽  
Ken-ichi Kondo ◽  
Kazutaka G. Nakamura
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Time Resolved ◽  
Electron Imaging
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