Toward Growing III-V Clusters with Metalorganic Precursors

1997 ◽  
Vol 468 ◽  
Author(s):  
A. Demchuk ◽  
J. Porter ◽  
B. Koplitz
Keyword(s):  
Excimer Laser ◽  
Vacuum Chamber ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Quadrupole Mass ◽  
Reaction Region ◽  
High Vacuum Chamber ◽  
Arf Excimer Laser ◽  
193 Nm ◽  
Pulsed Nozzle

ABSTRACTThe present work reports on the formation of GaN-containing clusters from metalorganic precursors by combining pulsed laser photolysis and pulsed nozzle methods. Ammonia (NH3) and triethylgallium (C2H5)3Ga (TEG) or trimethylgallium (CH3)3Ga (TMG) with He, Ar, or N2 as the carrier gas are introduced into a high vacuum chamber via a specialized dual pulsed nozzle source. The light from an ArF excimer laser (193 nm, 23 ns FWHM) is focused into the mixing and reaction region of the nozzle source, and the products are then mass analyzed with a quadrupole mass spectrometer. Efficient laser-assisted growth of (GaN)x-containing clusters is shown with this technique.

Low Temperature Laser-Assisted Gas Phase Reactivity of TMGa with NH3 and Oxygen-Containing Compounds (H2O, CH3OH, O(CH3)2) in Constrained Pulsed Expansions

2002 ◽  
Vol 743 ◽  
Author(s):  
Alexander Demchuk ◽  
Michael Lynch ◽  
Steven Simpson ◽  
Brent Koplitz
Keyword(s):  
Gas Phase ◽  
Vacuum Chamber ◽  
Cluster Formation ◽  
High Vacuum ◽  
Oxygen Species ◽  
Quadrupole Mass ◽  
High Vacuum Chamber ◽  
Arf Excimer Laser ◽  
Gas Nozzle ◽  
193 Nm

ABSTRACTThe present work reports on the study of III-V gas phase reactivity in constrained gas pulse expansions of trimethylgallium (TMGa) and oxygen derivative compounds (H2O, CH3OH, O(CH3)2) with and without ammonia. The precursors are introduced separately into a high vacuum chamber via a multipulsed gas nozzle assembly. The gas mixtures are then exposed to a UV pulse from an ArF excimer laser (λ=193 nm) and the products are mass analyzed with a quadrupole mass spectrometer. The efficient laser-assisted growth of Ga-O-containing clusters in the form of [(CH3)2GaOR] x, where R is H or CH3, has been revealed. Different behavior can be seen in the reaction of TMG and the oxygen species depending on the presence of H atoms bonded to the oxygen. Significant influence of NH3 on cluster formation and oxygen incorporation is demonstrated.

scholarly journals 193-nm deep-UV lithography system using a line-narrowed ArF excimer laser

1993 ◽  
Author(s):  
Bruce W. Smith ◽  
Malcolm C. Gower ◽  
Mark Westcott ◽  
Lynn F. Fuller
Keyword(s):  
Excimer Laser ◽  
Uv Lithography ◽  
Arf Excimer Laser ◽  
Deep Uv ◽  
193 Nm ◽  
Lithography System

Photon and thermal processing of CH3NH2-bearing ices. Synthesis of prebiotic species at low temperature (such as formamide, ethylamine, and methylcyanide), and N-heterocycles during warm up.

2021 ◽  
Author(s):  
Héctor Carrascosa ◽  
Cristóbal González Díaz ◽  
Guillermo M. Muñoz Caro ◽  
Pedro C. Gómez ◽  
María Luz Sanz
Keyword(s):  
Vacuum Chamber ◽  
Organic Molecules ◽  
Solid Phase ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Quadrupole Mass ◽  
Warm Up ◽  
Methyl Cyanide ◽  
Interstellar Ice ◽  
Complex Organic

<p>Hexamethylentetramine has drawn a lot of attention due to its potential to produce prebiotic species. This work aims to gain a better understanding in the chemical processes concerning methylamine under astrophysically relevant conditions. In particular, this work deeps into the formation of N-heterocycles in interstellar ice analogs exposed to UV radiation, which may lead to the formation of prebiotic species.</p> <p>Experimental simulations of interstellar ice analogs were carried out in ISAC. ISAC is an ultra-high vacuum chamber equipped with a cryostat, where gas and vapour species are frozen forming ice samples. Infrared and ultraviolet spectroscopy were used to monitor the solid phase, and quadrupole mass spectrometry served to measure the composition of the gas phase. The variety of species detected after UV irradiation of ices containing  methylamine revealed the presence of 12 species which have been already detected in the ISM, being 4 of them typically classified as complex organic molecules: formamide (HCONH<sub>2</sub>), methyl cyanide (CH<sub>3</sub>CN), CH<sub>3</sub>NH and CH<sub>3</sub>CHNH. Warming up of the irradiated CH<sub>3</sub>NH<sub>2</sub>-bearing ice samples lead to the formation of trimethylentriamine (TMT), a N-heterocycle precursor of HMT, and the subsequent synthesis of HMT at temperatures above 230 K.</p>

Study Of Al Surface Segregation In Icosahedral A162Cu25.5Fe12.5

1998 ◽  
Vol 553 ◽  
Author(s):  
M. GIL-GAVATZ ◽  
D. Rouxel ◽  
P. Pigeat ◽  
B. Weber ◽  
J.-M. Dubois
Keyword(s):  
Surface Segregation ◽  
Vacuum Chamber ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Spectrometer ◽  
Temperature Dependent ◽  
Self Diffusion ◽  
Different Temperatures ◽  
High Vacuum Chamber

AbstractSurface segregation of aluminium was observed during oxidation experiments of icosahedral A162Cu25.5 Fel12.5, performed in-situ and at different temperatures in the ultra-high vacuum chamber of a scanning Auger electron spectrometer. Two regimes, below and above 770K, were observed in relation with severe segregation of Al atoms at the surface for T > 770K. We postulate that this temperature dependent segregation rate is representative of the aluminium transport towards the surface of the quasicrystal. By analogy with classical diffusion experiments, we can thus determine reasonable estimates of the activation energy for Al self-diffusion in this quasicrystal. The results are consistent with the existence of phason flips below 770K and thermal vacancies above this temperature.

scholarly journals Fabrication of Superhydrophobic Silicone Rubber with Periodic Micro/Nano-Suction Cup Structure by ArF Excimer Laser-Induced Photodissociation

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 870 ◽  
Author(s):  
Masayuki Okoshi
Keyword(s):  
Excimer Laser ◽  
Silicone Rubber ◽  
Focal Point ◽  
Pulse Number ◽  
Entire Surface ◽  
Suction Cup ◽  
Atomic Force ◽  
Superhydrophobic Property ◽  
Arf Excimer Laser ◽  
193 Nm

A 193-nm ArF excimer laser was used to induce the photodissociation of Si–O bonds of silicone rubber in order to fabricate a periodic micro/nano-suction cup silicone structure, approximately 1 μm in diameter and 2 μm in height at regular intervals of 2.5 μm. The laser was focused on Al-coated silicone rubber by each silica glass microsphere 2.5 μm in diameter, which covered the entire surface of the silicone rubber. The silicone rubber underneath each microsphere photochemically swelled after laser-ablating the coated Al to limit the diameter of the swelling. Simultaneously, the coated Al was able to adjust the focal point to the surface of the silicone rubber to form a hole approximately 500 nm in diameter, centered at the swollen silicone. The dependences of the thickness of the coated-Al and the laser pulse number are discussed, based on the observations of a scanning electron microscope (SEM) and an atomic force microscope (AFM). The superhydrophobic property of the fabricated micro/nano-suction cup structure was successfully found.

Excimer Laser Induced Photochemistry of Silane-Ammonia Mixtures

1988 ◽  
Vol 131 ◽  
Author(s):  
J. M. Jasinski ◽  
D. B. Beach ◽  
R. D. Estes
Keyword(s):  
Mass Spectrometry ◽  
Steady State ◽  
Excimer Laser ◽  
Molecular Beam ◽  
Laser Shot ◽  
Time Resolved ◽  
Single Laser ◽  
Arf Excimer Laser ◽  
193 Nm

ABSTRACTSteady-state and time resolved molecular beam sampling mass spectrometry have been used to study the ArF excimer laser induced photochemistry of silaneammonia mixtures at 193 nm. Under both steady state and single laser shot conditions, products as complicated as tetraaminosilane are formed promptly. A mechanism which accounts for the formation of all observed products is proposed and evaluated.

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