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Chemical Vapour Deposition (CVD)

Chemical Vapour Deposition (CVD). David Xiulei Ji. Definition of typical CVD:. The vaporized precursors are introduced into a CVD reactor and adsorb onto a substance held at an elevated temperature. Either happens:. 1. Precursors decomposition (synthesis of CNT).

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Chemical Vapour Deposition (CVD)

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  1. Chemical Vapour Deposition (CVD) David Xiulei Ji Definition of typical CVD: The vaporized precursors are introduced into a CVD reactor and adsorb onto a substance held at an elevated temperature. Either happens: 1. Precursors decomposition (synthesis of CNT) 2. Precursors reaction with other gases or vapour to form crystal (synthesis of Metal Nitride)

  2. Typical Reactor and Process: Typical Reactor: Precursors, Carrier gases CVD process: • mass transport of reactants to the growth surface • (b) chemical reactions on the growth surface • (c) removal of undesired composition in the product.

  3. Growth Mechanism: Substrate Physical Review Letters (1990) 64 1943 Different growth mode decided by Interfacial free energy terms and lattice dismatch Thin film, Nano particles and Thin film&Nano particles

  4. Conditions That Matter in CVD • Reactants flow rate and different reactants • Reaction Temperature • Pressure of the system • Reacting Time: thickness of film or length of nano stuffs • Carrier gas: Argon, H2, Water…. to achieve slow homogeneous growth • Substrate: different types (Si, SiO2, Ni, quartz etc.) differently terminated ect. • Position of substrate in terms of gas flow

  5. More CVD Methods: a) LP PECVD: low pressured plasma enhanced CVD------utilized in industry Limitations: Not good for deposition of materials in a large scale. b) AP PECVD: Atmospheric pressured plasma enhanced CVD c) MO CVD: Metal organo CVD. Organic ligands as reducing agent. d) Catalytic CVD (Ni, Co, Fe nano particles) e) Template based CVD such as employ Aluminium Membrane

  6. One Successful Case: Carbon Nanotube (CNT): Initially synthesized under arc discharge method, one of CVD method. Ref: Nature, (1990), 347, 354 (C60) Nature, (1991), 354, 56 (First CNT) Chemical Reviews, 2005, Vol. 105, No. 4 1039

  7. Thank you Want to know more? Please go to the journal named Chemical Vapour Deposition

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