Periodicity and alignment of large-scale carbon nanotubes arrays

Intensive studies have been carried out on controlling the periodicity and alignment of large-scale periodic arrays of carbon nanotubes (CNTs) using plasma-enhanced chemical vapor deposition. Catalytic dots are first prepared by self-assembly of polystyrene spheres on chromium-coated silicon substrates. Preparation parameters for CNTs growth including temperature, thickness of catalytic dots, plasma current intensity, and pregrowth plasma etching time are fine tuned and analyzed to achieve optimal combinations. High-quality aligned CNTs arrays with long-range periodicity and controlled diameters have been achieved. The good periodicity and alignment are critical for their applications such as photonic crystals, negative index of refraction, etc.