Patterned growth of individual and multiple vertically aligned carbon nanofibers

The results of studies of patterned growth of vertically aligned carbon nan ofibers (VACNFs) prepared by plasma-enhanced chemical vapor deposition are reported. Nickel (Ni) dots of various diameters and Ni lines with variable widths and shapes were fabricated using electron beam lithography and evapo ration, and served for catalytic growth of VACNFs whose structure was deter mined by high resolution transmission electron microscopy. It is found that upon plasma pre-etching and heating up to 600-700 degrees C, thin films of Ni break into droplets which initiate the growth of VACNFs. Above a critic al dot size multiple droplets are formed, and consequently multiple VACNFs grow from a single evaporated dot. For dot sizes smaller than the critical size only one droplet is formed, resulting in a single VACNF. In the case o f a patterned line, the growth mechanism is similar to that from a dot. VAC NFs grow along the line, and above a critical linewidth multiple VACNFs are produced across the line. The mechanism of the formation of single and mul tiple catalyst droplets and subsequently of VACNFs is discussed. (C) 2000 A merican Institute of Physics. [S0003-6951(00)00824-X].