Growth of Uniform CNT Layer on Copper Foil-the Effect of Synthesis Methods/Conditions

Q. Zhang, J. Scofield, B. Tsao, J.N. Merrett, B.T. Quinton, J. Burke, N. Pierce
University of Dayton, US

Keywords: CNTs, synthesis, Cu foil


Carbon nanotubes (CNTs) with unique thermal/electrical/mechanical properties and large surface area are an attractive candidate for the integration into thermal structures and for a flexible thermal interface material in a thermal device. In this study, two different growing methods: thermal chemical vapor deposition (THCVD) and Floating catalyst chemical vapor deposition (FCCVD) have been used to investigate direct growth of high quality CNT layer on copper substrate. The SEM images and measurement/testing results indicated that the synthesis method, growth conditions/procedure and especially on substrate surface treatment play an important role with CNTs growth, size, and structure/morphology as well as interfacial and thermal performance. Using either THCVD or FCCVD, growth of CNTs on as received Cu foil with Fe as catalyst, only low dense, non-aligned CNT forest was grown on Cu substrate. However, a uniform, dense, aligned CNT layer could be successfully grown onto Cu foil in both THCVD and FCCVD method under design conditions when a thin buffer layer of Al2O3 was deposited on the cleaned Cu foil by sputtering or Atomic layer deposition (ALD) system prior to CNT growth. The length, alignment and areal density of CNTs can also be controlled by varying the thickness of Al2O3 layer.