Controlled surface diffusion in plasma-enhanced chemical vapor deposition of GaN nanowires

Research output: Contribution to journalArticle

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Abstract

This study investigates the growth of GaN nanowires by controlling the surface diffusion of Ga species on sapphire in a plasma-enhanced chemical vapor deposition (CVD) system. Under nitrogen-rich growth conditions, Ga has a tendency to adsorb on the substrate surface diffusing to nanowires to contribute to their growth. The significance of surface diffusion on the growth of nanowires is dependent on the environment of the nanowire on the substrate surface as well as the gas phase species and compositions. Under nitrogen-rich growth conditions, the growth rate is strongly dependent on the surface diffusion of gallium, but the addition of 5% hydrogen in nitrogen plasma instantly diminishes the surface diffusion effect. Gallium desorbs easily from the surface by reaction with hydrogen. On the other hand, under gallium-rich growth conditions, nanowire growth is shown to be dominated by the gas phase deposition, with negligible contribution from surface diffusion. This is the first study reporting the inhibition of surface diffusion effects by hydrogen addition, which can be useful in tailoring the growth and characteristics of nanowires. Without any evidence of direct deposition on the nanowire surface, gallium and nitrogen are shown to dissolve into the catalyst for growing the nanowires at900°C.

Original languageEnglish
Article number055606
JournalNanotechnology
Volume20
Issue number5
DOIs
Publication statusPublished - 2009 Apr 20

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Surface diffusion
Plasma enhanced chemical vapor deposition
Nanowires
Gallium
Hydrogen
Nitrogen
Gases
Nitrogen plasma
Aluminum Oxide
Substrates
Sapphire
Catalysts
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)

Cite this

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abstract = "This study investigates the growth of GaN nanowires by controlling the surface diffusion of Ga species on sapphire in a plasma-enhanced chemical vapor deposition (CVD) system. Under nitrogen-rich growth conditions, Ga has a tendency to adsorb on the substrate surface diffusing to nanowires to contribute to their growth. The significance of surface diffusion on the growth of nanowires is dependent on the environment of the nanowire on the substrate surface as well as the gas phase species and compositions. Under nitrogen-rich growth conditions, the growth rate is strongly dependent on the surface diffusion of gallium, but the addition of 5{\%} hydrogen in nitrogen plasma instantly diminishes the surface diffusion effect. Gallium desorbs easily from the surface by reaction with hydrogen. On the other hand, under gallium-rich growth conditions, nanowire growth is shown to be dominated by the gas phase deposition, with negligible contribution from surface diffusion. This is the first study reporting the inhibition of surface diffusion effects by hydrogen addition, which can be useful in tailoring the growth and characteristics of nanowires. Without any evidence of direct deposition on the nanowire surface, gallium and nitrogen are shown to dissolve into the catalyst for growing the nanowires at900°C.",
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Controlled surface diffusion in plasma-enhanced chemical vapor deposition of GaN nanowires. / Hou, Wen Chi; Hong, Franklin Chau-Nan.

In: Nanotechnology, Vol. 20, No. 5, 055606, 20.04.2009.

Research output: Contribution to journalArticle

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