Synthetic Metals 148 (2005) 263–266 Synthesis of carbon nanotubes with identical dimensions using an anodic aluminum oxide template on a silicon wafer Ok-Joo Lee a,∗,1 , Sun-Kyu Hwang b,1 , Soo-Hwan Jeong c , Pyung Soo Lee b , Kun-Hong Lee b a Basic Research Laboratory, Electronics and Telecommunications Research Institute (ETRI), Gajeong-dong, Yuseong-gu, Daejeon 305-350,South Korea b Department of Chemical Engineering, Computer and Electrical Engineering Division, Pohang University of Science and Technology (POSTECH), Pohang 790-784, South Korea c U team, Samsung Advanced Institute of Technology (SAIT), Suwon 440-600, South Korea Received 27 July 2004; received in revised form 4 October 2004; accepted 5 October 2004 Available online 23 November 2004 Abstract Anodic aluminum oxide (AAO) templates with uniform channels of sub-micron length were fabricated on silicone wafers. Carbon was deposited on the wall of the pores via decomposition of acetylene at 800 ◦ C. The synthesized carbon nanotubes have identical dimensions of 900 nm in length and 70 nm in diameter. Raman spectrum showed that the crystallinity of these CNTs is relatively high though no catalyst was used. The proposed technique can be applied to the fabrication of vacuum microelectronic devices. © 2004 Elsevier B.V. All rights reserved. Keywords: Carbon nanotube; Anodic aluminium oxide (AAO); Thin film aluminium; Thin film alumina; Raman spectrum 1. Introduction Carbon nanotubes (CNTs) have drawn much attention because of their unique physical properties and wide vari- ety of applications [1,2]. Various methods for the synthesis of CNTs have been reported: arc-discharge [3], laser abla- tion [4], chemical vapor deposition [5], high-pressure CO (HiPCO) process [6] and microwave synthesis [7]. Although the ability to control the morphology and the crystallinity of CNTs have been progressing continuously, current state-of- the-art still needs much improvement to be applied to the fabrication of real electronic devices. In particular, a tech- nique which is able to synthesize CNTs with a uniform size and high purity is highly desirable and is thought to be an ∗ Corresponding authors. Present address: Max Planck Institute for Poly- mer Research, Ackermanweg 10, D-55128 Mainz, Germany. Tel. +49 6131 379 366; fax: +49 6131 379 100. E-mail address: okjoo@mpip-mainz.mpg.de (O.-J. Lee). 1 These authors contributed equally to this work. important technical element in the application of CNTs in electronic devices. A simple and effective method to control the dimensions of CNTs is to use templates. Mesoporous silica was used as the template in the synthesis of CNTs with similar diame- ters [8]. Anodic aluminum oxide (AAO) templates have also been widely used [9,10]. An AAO template has uniform and straight channels, the dimensions of which can be controlled by applied voltage, type of electrolyte and temperature [11]. Various metal nanowires as well as CNTs have been synthe- sized, taking advantage of the straight channel structure of AAO templates [12–15]. Research on the synthesis of CNTs in AAO templates can be classified into two categories: works in the first category use high-purity Al sheets [16,17]. The temperature of CNT synthesis, however, is limited to below 660 ◦ C by the pres- ence of the unanodized aluminum under the AAO template, resulting in poor crystallinity of CNTs. Complete anodization of the Al sheet can avoid this problem, though the synthesized CNTs are usually too long to be used in electronic devices [9]. 0379-6779/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2004.10.005