Highly aligned carbon nanotubes (NTs) have been directly grown on metallic surfaces and in the channel,, of anodic aluminum oxide (AAO) templates at a low temperature by bias-enhanced microwave plasma chemical vapor deposition. Microwave plasma generated nanoparticles of various sizes (10-100 nm) on metallic surfaces, which acted as the catalyst for the formation of free-standing NTs. NTs with diameters of 40-50 nm had a high growth rate in the vertical direction, resulting in the formation of carbon tube arrays. The formation of NTs in the channels of AAO at the same experiment condition was a layer-by-layer deposition process of graphite.