scholarly journals Influence of Gas Sort on the Nucleation Region Width of Si Nanocrystal Grains Prepared by Pulsed Laser Ablation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zechao Deng ◽  
Lizhi Chu ◽  
Xuecheng Ding ◽  
Aili Qin ◽  
Guangsheng Fu ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Gas Flow ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Effective Energy Transfer ◽  
Si Nanocrystal ◽  
Mean Size ◽  
Ambient Gases ◽  
Ambient Gas

We have calculated the nucleation region (NR) location of Si nanocrystal grains prepared by pulsed laser ablation (PLA) with fluence of 4 J/cm2 in 10 Pa gas at room temperature, and ambient gases were He, Ne, and Ar, respectively. Results of calculation indicated that NR width in Ne gas was narrowest, while it was widest in He gas. Maximum mean size of grains deposited on substrates under ablated spot, which were placed horizontally, was the smallest in Ne gas. It would be attribute to more effective energy transfer during the process of collision when atomic mass of Si and ambient gas Ne are more close to each other. In this work, an additional gas flow with the same element as ambient gas was introduced, which is vertical to the plume axis at different lateral positions above ablated spot.

Silicon and zinc telluride nanoparticles synthesized by low energy density pulsed laser ablation into ambient gases

1999 ◽  
Vol 14 (2) ◽  
pp. 359-370 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Christopher M. Rouleau ◽  
T.G. Thundat ◽  
G. Duscher ◽  
E.A. Kenik ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Energy Density ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Gas Pressure ◽  
Low Energy ◽  
Crystalline Core ◽  
Ambient Gases ◽  
The Mean ◽  
Ambient Gas

The size distributions of Si and ZnTe nanoparticles produced by low energy density ArF (193 nm) pulsed laser ablation into ambient gases were measured as a function of the gas pressure, P, and target-substrate separation, Dts. For both Si and ZnTe, the largest nanoparticles were found closest to the ablation target, and the mean nanoparticle size decreased with increasing Dts. For Si ablation into He, the mean nanoparticle diameter did not increase monotonically with gas pressure but reached a maximum near P = 6 Torr. High resolution Z-contrast transmission electron microscopy and energy loss spectroscopy revealed that ZnTe nanoparticles consist of a crystalline core surrounded by an amorphous ZnO shell; growth defects and surface steps are clearly visible in the crystalline core. A pronounced narrowing of the ZnTe nanocrystal size distribution with increasing Dts also was found. The results demonstrate that the size of laser-ablated nanoparticles can be controlled by varying the molecular weight and pressure of an ambient gas and that nanometer-scale particles can be synthesized. Larger aggregates of both ZnTe and Si having a “flakelike” or “weblike” structure were formed at the higher ambient gas pressures; for ZnTe these appear to be open agglomerates of much smaller (∼10 nm) particles.

scholarly journals Width of Nucleation Region of Si Nanocrystal Grains Prepared by Pulsed Laser Ablation with Different Laser Fluence

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zechao Deng ◽  
Xuexia Pang ◽  
Xuecheng Ding ◽  
Lizhi Chu ◽  
Yinglong Wang
Keyword(s):  
Laser Ablation ◽  
Laser Fluence ◽  
Langmuir Probe ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Experimental Results ◽  
Initial Formation ◽  
Si Nanocrystal ◽  
Ar Gas

Si nanocrystal grains were prepared by pulsed laser ablation with different laser fluence in Ar gas of 10 Pa at room temperature. The as-formed grains in the space deposited on the substrates and distributed in a certain range apart from target. According to the depositing position and radius of grains, the nucleation locations of grains in the space were roughly calculated. The results indicated that the width of nucleation region broadened with increasing of ion densities diagnosed by Langmuir probe, which increased with laser fluence from 2 J/cm2 to 6 J/cm2; that is, width of nucleation region broadened with addition of laser fluence. At the same time, the width broadened with the terminal formation position moving backward and the initial formation position of grains moving toward ablated spot. The experimental results were explained reasonably by nucleation thermokinetic theory.

Formation of surface stabilized Si nanocrystal by pulsed laser ablation in hydrogen gas

2008 ◽  
Vol 93 (3) ◽  
pp. 717-720 ◽  
Author(s):  
Ikurou Umezu ◽  
Issei Kondo ◽  
Akira Sugimura
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Hydrogen Gas ◽  
Si Nanocrystal

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.

Influence of additional gas flow on size distribution of Si nanoparticles deposited by pulsed laser ablation

2010 ◽  
Vol 22 (9) ◽  
pp. 2199-2202
Author(s):  
王英龙 Wang Yinglong ◽  
罗青山 Luo Qingshan ◽  
邓泽超 Deng Zechao ◽  
褚立志 Chu Lizhi ◽  
丁学成 Ding Xuecheng ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Size Distribution ◽  
Gas Flow ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Si Nanoparticles

scholarly journals Влияние бора на структуру и проводимость тонких пленок, получаемых лазерной абляцией алмаза при 700-=SUP=-o-=/SUP=-C

2018 ◽  
Vol 44 (12) ◽  
pp. 16
Author(s):  
Р.И. Романов ◽  
В.Ю. Фоминский ◽  
П.В. Зинин ◽  
И.А. Троян ◽  
Д.В. Фоминский ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Room Temperature ◽  
Diffusion Processes ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Diamond Powder ◽  
Atomic Ratio ◽  
Film Deposition ◽  
Chemical Bonds ◽  
Boron Powder

AbstractStructural features of CB_ x films obtained by pulsed laser ablation of targets made of pressed diamond powder with boron-powder additions at B/C atomic ratio of x = 0.33 have been studied. The films were deposited on heated substrates, so that diffusion processes involving C and B atoms on the surface and in the volume of films were possible. Selected conditions of film deposition ensured their effective doping with boron (0.4 ≤ x ≤ 0.6). The incorporation of B atoms was accompanied by the formation of B–C chemical bonds, whereas the formation of sp ^2 graphite bonds and their ordering in clusters with laminar packing was suppressed. The films possessed very low resistivity (~1.4 mΩ cm) at room temperature and exhibited metallic type of conductance on decreasing the temperature to 77 K.

Characterization of copper oxide deposited on α-Al2O3 by pulsed-laser ablation

1993 ◽  
Vol 51 ◽  
pp. 1152-1153
Author(s):  
M.W. Bench ◽  
K.B. Sartain ◽  
M.P. Mallamaci ◽  
C.B. Carter
Keyword(s):  
Laser Ablation ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Oxide System ◽  
Reaction Products ◽  
Adhesion Properties ◽  
Copper Aluminate ◽  
Α Al2o3

The Cu-Al-O system is of considerable interest for electronic packaging, where thin copper wires are bonded to alumina substrates. In order to optimize the adhesion properties of Cu to alumina, it has been suggested that a ternary bonding environment is necessary at the interface. In comparison to a model oxide system such as NiO/alumina, where NiO is the only stable oxide of Ni and only one phase forms during the reaction, the situation is more complex in the Cu-Al-O system. First, two oxides of copper can form with CuO stable at room temperature and Cu2O stable above 1020°C in air. In addition, two copper aluminate reaction products (CuAl2O4 and CuAlO2) can form in the Cu-Al-O system. In a previous study it was found that both form during reactions in air at 1100°C, with the relative positions of each dependent on the crystallographic orientation of the alumina substrate.

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