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Title: Method of growing films by flame synthesis using a stagnation-flow reactor

Abstract

A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.

Inventors:
 [1];  [2]
  1. (Dublin, CA)
  2. (Sunnyvale, CA)
Publication Date:
Research Org.:
SANDIA CORP
OSTI Identifier:
871989
Patent Number(s):
US 5840373
Assignee:
Sandia Corporation (Livermore, CA) SNL
DOE Contract Number:
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; growing; films; flame; synthesis; stagnation-flow; reactor; stabilizing; strained; stagnation; flow; causing; highly; divided; equal; size; segments; stablize; verge; extinction; providing; film; growth; rates; stabilizer; annular; mounted; coaxially; coplanar; substrate; vertical; pillars; top; surface; increasing; azimuthal; nodes; preserving; axisymmetric; structure; stability; strained flame; stagnation flow; growth rate; film growth; top surface; flow reactor; flame stabilizer; growth rates; highly strained; size segments; growing films; equal size; flame synthesis; mounted coaxial; /427/

Citation Formats

Hahn, David W., and Edwards, Christopher F. Method of growing films by flame synthesis using a stagnation-flow reactor. United States: N. p., 1998. Web.
Hahn, David W., & Edwards, Christopher F. Method of growing films by flame synthesis using a stagnation-flow reactor. United States.
Hahn, David W., and Edwards, Christopher F. Thu . "Method of growing films by flame synthesis using a stagnation-flow reactor". United States. doi:. https://www.osti.gov/servlets/purl/871989.
@article{osti_871989,
title = {Method of growing films by flame synthesis using a stagnation-flow reactor},
author = {Hahn, David W. and Edwards, Christopher F.},
abstractNote = {A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1998},
month = {Thu Jan 01 00:00:00 EST 1998}
}

Patent:

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  • A method is described for stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided andmore » preserving an axisymmetric structure necessary for stability. 5 figs.« less
  • A method is described for stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stabilize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided andmore » preserving an axisymmetric structure necessary for stability.« less
  • A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving anmore » axisymmetric structure necessary for stability.« less
  • Flame-synthesis limits of carbon nanotubes (CNTs) are measured using a double-faced wall stagnation flow (DWSF) burner that shows potential in mass production of CNTs. With nitrogen-diluted premixed ethylene-air flames established on the nickel-coated stainless steel double-faced plate wall, the limits of CNT formation are determined using field-emission scanning and transmission electron microscopies and Raman spectroscopy. Also, self-catalytic behavior of the synthesized CNTs is evaluated using the DWSF burner with a CNT-deposited stainless steel double-faced plate wall. Results show narrow fuel-equivalence ratio limits of multi-walled CNT (MWCNT)-synthesis at high flame stretch rates and substantially extended limits at low flame stretch rates.more » This implies that the synthesis limits are very sensitive to the fuel-equivalence ratio variation for the high stretch rate conditions, yielding a lot of impurities and soot rather than MWCNTs. The enhanced ratio of tube inner diameter to wall thickness of the MWCNTs synthesized using a CNT self-catalytic flame-synthesis process is observed, indicating that the quality of metal-catalytic, flame-synthesized MWCNTs can be much improved via the process. Thus, using a DWSF burner with the CNT self-catalytic process has potential in mass production of MWCNTs with improved quality. (author)« less
  • A method and apparatus for the rapid and economical deposition of uniform and high quality films upon a substrate for subsequent use in producing electronic devices, for example. The resultant films are either epitaxial (crystalline) or amorphous depending upon the incidence rate and the temperature and structure of the substrate. The deposition is carried out in a chamber maintained at about 10.sup.-6 Torr. A gaseous source of the material for forming the deposit is injected into the deposition chamber in the form of a pulsed supersonic jet so as to obtain a high incidence rate. The supersonic jet is producedmore » by a pulsed valve between a relatively high presure reservoir, containing the source gaseous molecules, and the deposition chamber; the valve has a small nozzle orifice (e.g., 0.1-1.0 mm diameter). The type of deposit (crystalline amorphous) is then dependent upon the temperature and structure of the substrate. Very high deposition rates are achieved, and the deposit is very smooth and of uniform thickness. Typically the deposition rate is about 100 times that of much more expensive conventional molecular beam methods for deposition, and comparable to certain expensive plasma-assisted CVD methods of the art. The high growth rate of this method results in a reduced contamination of the deposit from other elements in the environment. The method is illustrated by the deposition of epitaxial and amorphour germanium films upon GaAs substrates.« less