Office of Technology Transfer – University of Michigan

Ultrafast laser modulation of catalytic chemical vapor deposition

Technology #6811

Carbon nanotubes are nanostructures of carbon that have extraordinary mechanical and electrical properties with applications in many fields of materials and technology. However, mass production of sizeable nanotube structures continues to prove challenging. Chemical vapor deposition (CVD) is a leading method of carbon nanotube production, but a large number of control factors such as the types and quantities of substrates, catalysts, and gasses, the temperature of the reaction, and the duration of the reaction create a complex problem for optimizing growth. Now, a new method of ultrafast laser irradiation for CVD promises to increase nanotube yields in non-optimized conditions and bring effective mass production of nanotubes closer to reality.

Short burst of laser radiation enhances nanotube growth

By using femtosecond-length bursts of laser radiation on a catalyzed surface undergoing chemical vapor deposition, carbon nanotube growth height can be greatly enhanced without optimized growth conditions. The same laser can also be used to suppress growth in certain areas, allowing the laser to selective pattern growth without contact or preprocessing of the catalyst such as in photolithography or printing. This can be useful in cases where a solvent may damage the substrate, for example. Initial testing has demonstrated increased nanotube forest heights by up to a factor of 50 without any other change to the CVD process.

Applications

  • Increase yields of nanotubes from chemical vapor deposition
  • Selectively pattern nanotube growth without contact or catalyst preprocessing

Advantages

  • Reduces cost and production time by allowing efficient nanotube production without optimizing process
  • Significantly increases ultimate nanotube height
  • Pattern nanotube growth without additional process steps