Fabrication of patterned domains with graphitic clusters in amorphous carbon using a combination of ion implantation and
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0908-OO11-05.1
Fabrication of patterned domains with graphitic clusters in amorphous carbon using a combination of ion implantation and electron irradiation techniques Eiji Iwamura1 and Tatsuhiko Aizawa2 1 PRESTO, Japan Science and Technology Agency Arakawa Chemical Industries, LTD, 1-1-9 Tsurumi, Tsurumi-ku Osaka 539-0053, Japan 2 Department of Materials Science and Engineering, University of Toronto Room, 140, 184 College Street, Toronto, Ontario, Canada M5S 3E4 Japan office, 1-24-12 Shinkawa, Chuo-ku, Tokyo 104-0033, Japan ABSTRACT Fabrication of domains containing graphitic structures in amorphous carbon (a-C) films was demonstrated. Amorphous carbon thin films with 200 nm thickness were deposited on Si substrates by ion-beam sputtering. Iron atoms in a range from 4×1013 to 3.7×1016 cm-2 were doped to the a-C films by an ion implantation technique through a nickel mask with a grid of square windows of 500×500 µm and a net of 50 µm in width as a template. After removing the metal mask, the partly Fe-containing a-C films were exposed to a low-energy electron shower. In the regions where Fe atoms were implanted, Fe were crystallized and preferably diffused toward the film surface leaving graphitic structures more than 10 nm in size in the interior of the amorphous carbon films. On the other hand, the masked regions, where Fe atoms were not implanted, remained amorphous. The results suggest that regions, which consist of amorphous domains and graphitic domains, can be intentionally arranged in a-C thin films.
INTRODUCTION A new form of carbon incorporating graphitic structures in amorphous carbon networks has attracted extensive interests since the hybridized structures are expected to lead to high performances by combining diverse physical properties, which arise from carbon structures. Various techniques have been used in synthesizing graphitic structures in combination with amorphous carbon films. However, as the ordered carbon structures are generally the forms as a result of high energy, in most cases, structural ordering of carbon atoms strongly depends on complex plasma or film forming processes [1-5]. They usually require special forming conditions, such as highly-energetic particles, high temperature, high pressure or ultra high vacuum. It is reported that carbon hybrid structures were synthesized at relatively low temperature using low-energy electron irradiation [6,7]. Onion-like and nano-crystalline graphitic structures in amorphous carbon matrices were fabricated via dynamic structural modification which works in converting from amorphous to ordered structures with a help of catalytic metal dopants. This technique implies that it is possible to make an intentionally arranged patterns consisting of domains of ordered/disordered carbon by controlling the region where catalytic elements are doped. In this study, fabrication of carbon composite structures, which contain patterned domains with graphitic structures in amorphous matrix, was investigated. Iron atoms were doped by using an ion-implantation tec
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