Synthesis of nanostructured ZnO by laser ablation in a background gas

2004 ◽  
Author(s):  
Tatsuo Okada ◽  
Kou Kawashima ◽  
Yoshiki Nakata
Keyword(s):  
Laser Ablation ◽  
Background Gas

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.

Size classification of Si nanoparticles formed by pulsed laser ablation in helium background gas

1999 ◽  
Vol 69 (S1) ◽  
pp. S243-S247 ◽  
Author(s):  
T. Makino ◽  
N. Suzuki ◽  
Y. Yamada ◽  
T. Yoshida ◽  
T. Seto ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Size Classification ◽  
Si Nanoparticles ◽  
Background Gas

Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis

2007 ◽  
Vol 101 (2) ◽  
pp. 023115 ◽  
Author(s):  
Sy-Bor Wen ◽  
Xianglei Mao ◽  
Ralph Greif ◽  
Richard E. Russo
Keyword(s):  
Laser Ablation ◽  
Experimental Analysis ◽  
Plume Expansion ◽  
Vapor Plume ◽  
Background Gas

Dynamics of colliding laser ablation plumes in background gas

2016 ◽  
Vol 122 (4) ◽  
Author(s):  
Ikurou Umezu ◽  
Yusuke Hashiguchi ◽  
Hiroshi Fukuoka ◽  
Naomichi Sakamoto ◽  
Tamao Aoki ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Background Gas

Non-equilibrium Growth Processes of Porous TiO2 Nanocrystal-films during Pulsed Laser Ablation

2013 ◽  
Vol 1497 ◽  
Author(s):  
Ikurou Umezu ◽  
Nobuyasu Yagi ◽  
Akira Sugimura ◽  
Takehito Yoshida
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Hierarchical Structures ◽  
Pulsed Laser Ablation ◽  
Rutile Phase ◽  
Gas Pressure ◽  
Target Distance ◽  
Structural Formation ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTWe performed pulsed laser ablation of titanium dioxide (TiO2) target in O2 background gas. Effects of background gas pressure and substrate target distance on the structure of deposited films are clarified. The hierarchical structures are observed when we change scale of observation. The film deposited on the substrate is composed of primary nanocrystal and secondary porous-aggregated-nanostructures. The primary nanocrystal changes from anatase to rutile phase with increasing background gas pressure or substrate target distance. The porosity of secondary aggregated structure increases with increasing background gas pressure or substrate target distance. The similarity between the effects of background gas and substrate target distance indicates that confinement of the plume between target and substrate is important for structural formation. The non-equilibrium aggregation processes of nanocrystals in the plume and on the substrate are essential for the hierarchical structure of the nanocrystal film.

Computer Simulations of Laser Ablation, Plume Expansion and Plasma Formation

2011 ◽  
Vol 227 ◽  
pp. 1-10 ◽  
Author(s):  
Annemie Bogaerts ◽  
Maryam Aghaei ◽  
David Autrique ◽  
Helmut Lindner ◽  
Zhao Yang Chen ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Plasma Formation ◽  
Local Thermal Equilibrium ◽  
Temperature Model ◽  
Plume Expansion ◽  
Conduction Model ◽  
First Results ◽  
Dynamics Simulations ◽  
Background Gas ◽  
Two Temperature

An overview is given of different modeling work that has been carried out, and is currently going on in our research group, in the field of modeling for laser ablation (LA). Most emphasis will be put on nanosecond (ns) LA, more specifically describing the laser-solid interaction, leading to heating, melting and vaporization of the target, by a heat conduction model, the expansion of the evaporated plume in vacuum or in a background gas by a set of conservation equations, and the plasma formation in the plume, assuming local thermal equilibrium. Some first results for nanoparticle formation in the expanding plume will be presented as well. Also, the process of target heating in the case of femtosecond (fs) LA will be described by means of a two-temperature model, and phase transitions, more specifically evaporation, will be illustrated by means of molecular dynamics simulations.

Influence of the atomic mass of the background gas on laser ablation plume propagation

2008 ◽  
Vol 92 (4) ◽  
pp. 907-911 ◽  
Author(s):  
Salvatore Amoruso ◽  
Jørgen Schou ◽  
James G. Lunney
Keyword(s):  
Laser Ablation ◽  
Atomic Mass ◽  
Ablation Plume ◽  
Background Gas
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