Selective Growth of Aligned Co‐Filled Carbon Nanotubes on Silicon Substrates

We report on a method for the selective growth of aligned cobalt (Co)‐filled multi‐walled carbon nanotubes (MWNTs) using the pyrolysis of cobaltocene. The nanotubes grow preferentially on Fe structures patterned onto SiO2/Si substrates by a lift‐off process. The filling is discontinuous and forms a sequence of nanowire segments located along the tube. The nanowires consist of single crystalline grains with fcc structure. They have diameters of 10–20 nm and their length reaches several hundred nanometers. Our method allows the building of a system of oriented MWNTs filled with ferromagnets. It may be applied for fabricating nanotube‐based microelectronic devices.