Three-dimensional micropatterns of well-aligned carbon nanotubes produced by photolithography.

Three-dimensional micropatterns of well-aligned carbon nanotubes were prepared on photolithographically prepatterned substrates by pyrolysis of iron(II) phthalocyanine (FePc) under an Ar/H2 atmosphere at 800-1100 degrees C. The photopatterning was achieved by photolithographic cross-linking of a chemically amplified photoresist layer spin-cast on a quartz plate or a silicon wafer, coupled with solution development. Owing to an appropriate surface characteristic, the patterned photoresist layer was found in this case to support aligned carbon nanotube growth by pyrolysis of FePc, as were the photoresist-free substrate surfaces. The difference in chemical nature between the surface areas covered and uncovered by the photoresist film, however, caused a region-specific growth of the nanotubes with different tubular lengths and packing densities, leading to the formation of three-dimensional aligned nanotube patterns suitable for various device applications.