Selective growth of individual multiwalled carbon nanotubes q R.E. Morjan a , M.S. Kabir b , S.W. Lee a,c , O.A. Nerushev a,1 , P. Lundgren b , S. Bengtsson b , Y.W. Park c , E.E.B. Campbell a, * a Department of Experimental Physics, School of Physics and Engineering Physics, G€ oteborg University and Chalmers University of Technology, SE-41296 G€ oteborg, Sweden b Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 G€ oteborg, Sweden c School of Physics and Condensed Matter Research Institute, Seoul National University, Seoul 151-747, South Korea Received 20 November 2003; accepted 30 January 2004 Available online 25 March 2004 Abstract Growth of individual, vertically aligned multiwalled carbon nanotubes (VACNT) on patterned Si wafers using dc plasma- enhanced CVD is described. The selective growth of individual VACNT within larger holes etched in Si is demonstrated for the first time. Ó 2004 Elsevier B.V. All rights reserved. PACS: 81.07.De Keywords: Plasma-enhanced chemical vapour deposition; PECVD; Multiwalled carbon nanotubes; Controlled individual growth 1. Introduction Nanodevice fabrication based on carbon nanotubes requires a robust and highly reproducible technique to control the growth of nanotubes in specific locations with defined orientation in different configurations. One very promising technique is the growth of individual vertically aligned carbon nanotubes (VACNT) or car- bon fibres using plasma-enhanced chemical vapour deposition (PE-CVD) in the presence of Ni catalyst particles [1–5]. It is clear from these studies that PE- CVD is a high yield and controllable method of pro- ducing VACNT. These structures have been studied so far mainly for their application as efficient field emitters [6] but very recent reports also suggest their applications as templates for producing nanopipes [7] or as electrochemical sensors [8]. In this paper we report studies of the growth of VACNT on patterned Ni cat- alysts and demonstrate the reproducible production of individual VACNT growing in a much wider hole etched in Si. These structures are of interest for developing e.g., field emission or nanoelectromechanical applications. 2. Experimental procedure The growth was performed in a dc PE-CVD setup that has been described in detail previously in a publi- cation concerning PE-CVD growth of aligned MWNT films from Fe catalyst particles [9]. The dc glow dis- charge plasma was produced by applying a voltage of 400 V to an anode situated 12 mm from the grounded substrate. The gas mixture used was a 1:5 ratio of C 2 H 2 :NH 3 at a pressure of 4 Torr. The first planar substrates used in the initial experiments were prepared by depositing a thin, 10 nm thick layer of Ni on the silicon substrates (with a 2 nm thick native oxide layer). This produced films of aligned nanotubes with varying diameter as shown in Fig. 1. The next stage was to prepare patterns of Ni dots with a diameter of 50 nm. Finally, a pattern of 500 nm diameter holes was q Original version presented at QTSM&QFS 2003 (Quantum Transport Synthetic Metals & Quantum Functional Semiconductors), Seoul National University, Seoul, Korea, 20–22 November 2003. * Corresponding author. Tel.: +46-31-772-3272; fax: +46-31-772- 3496. E-mail address: eleanor.campbell@fy.chalmers.se (E.E.B. Camp- bell). 1 Present address: Institute of Thermphysics, RAS, Novosibirsk 630090, Russia. 1567-1739/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.cap.2004.01.025 www.elsevier.com/locate/cap Current Applied Physics 4 (2004) 591–594