Synthesis of Metal Oxide Nanoparticles by Flame Method

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Synthesis of Metal Oxide Nanoparticles by Flame
Method
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Plasma Spray Process                            
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                      Schematic Diagram of the
Plasma Spray Process
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Wet Technologies for the Formation ofOrganic
Nanostructures
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• Chemical methods of material processing were
  known for years, existing in parallel with
  physical methods of film deposition. Recent
  advances in electron microscopy and scanning
  nanoprobe microscopy (STM, AFM) have revealed
  that some of the materials produced by the
  chemical methods have distinctive nanocrystalline
  structure. Furthermore, due to the achievements
  of colloid chemistry in the last 20 years, a
  large variety of colloid nanoparticles have
  become available for film deposition. This has
  stimulated great interest in further development
  of chemical methods as cost-effective
  alternatives to such physical methods as thermal
  evaporation magnetron sputtering chemical and
  physical vapor deposition (CVD, PVD) and
  molecular beam epitaxy (MBE). This chapter will
  review chemical methods of film deposition, with
  the emphasis on novel techniques for
  nanostructured materials processing.

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Self-Assembly of Colloid Nanoparticles

• The deposition of colloid nanoparticles onto
  solid substrates can be accomplished
• by different methods, such as simple casting,
  electrostatic deposition, Langmuir-
• Blodgett, or spin coating techniques, which will
  be discussed in detail later in this
• course. However, the simplest method of
  nanoparticles deposition, which gives
• some remarkable results, is the so-called
  self-assembly or chemical self-assembly
• method. This method, which was first introduced
  by Netzer and Sagiv 12, is based
• upon strong covalent bonding of the adsorbed
  objects (i.e., monomer or polymer
• molecules and nanoparticles) to the substrate via
  special functional groups.

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Electrodeposition of Nanostructured Materials

• Electrodeposition is one of the first chemical
  (or rather electrochemical) methods for the
  formation of inorganic coatings on solid
  surfaces. The formation of metal coatings on the
  anode by means of electrolysis of respective
  metal salts has been known since the nineteenth
  century. During the last few decades, this method
  has spread to other materials, such as II-VI and
  II-V semiconductor materials, with the main
  application in photovoltaic devices and solar
  cells.

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The first route is more traditional, and is based
on the well-developed technique of
electroplating. In order to form nanostructured
materials, some kind of surfactants should be
added to the electrolyte solution. The
surfactants act as a stabilizing agent to coat
nanocrystals and to prevent them from further
aggregation, and therefore the formation of large
grains of material. The review papers 20, 21
present a variety of materials, including metals,
semiconductors, ceramics, and polymers,deposited
in this way. A classical example of gold
nanoparticles deposition is given in 22.
Monodispersed gold nanoparticles of a few
nanometers were fabricated and deposited
simultaneously on the silicon surface by the
galvanostatic reduction of HAuCl4 in the presence
of dodecanethiol.
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Schematic diagram of spurting machine
www.angstromsciences.com, 2002.
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Spin Coating

• The method of spin coating was known for decades
  as a main technique for the
• deposition of polymer layers onto flat solid
  surfaces, and particularly for photoresist
• deposition in microelectronics fabrication. The
  idea is very simple, and consists of
• spreading of a polymer solution onto the
  substrate fixed on a stage, rotating at a
• speed in the order of thousands of revolutions
  per minute. Under the influence of the
• central force, the polymer solution spreads
  evenly over the large area and dries out,
• due to the solvent evaporation during the
  rotation. After additional baking at elevated
  temperatures, a polymer layer is finally formed
  on the surface.

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