Vacuum 82 (2008) 359–362 Short communication Carbon nanopillar array deposition on SiO 2 by ion irradiation through a porous alumina template M. Skupin´ski a , A. Johansson a , T. Jarmar a , A. Razpet b , K. Hjort a , M. Boman a , G. Possnert a , J. Jensen a,Ã a The A ˚ ngstro¨m Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden b Department for Low and Medium Energy Physics, Joz˘ef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia Received 23 January 2007; received in revised form 2 May 2007; accepted 21 May 2007 Abstract A method for producing ordered carbon nanopillar arrays is presented. The method is based on ion irradiation through a small anodic porous alumina membrane, resulting in carbon deposition within the centers of the pores on a gold covered SiO 2 =Si substrate. Samples were irradiated by 4 MeV Cl 2þ ions with fluences of 10 15 210 16 ions=cm 2 . The combined use of pick’n place positioning of the small porous alumina templates and ion beam irradiation is well suited for post-processing on silicon based integrated circuits. It provides fast local deposition at low temperature of high-density ordered carbon nanopillar arrays in larger silicon based systems, e.g., for field emitting or biosensors applications. r 2007 Elsevier Ltd. All rights reserved. PACS: 61.46.Fg; 61.80.Jh; 81.07.b; 81.16.c; 81.16.Dn; 85.40.Hp Keywords: SiO 2 ; Carbon nanostructures; Carbon pillars; Ion lithography; Ion irradiation; Anodic porous alumina membrane 1. Introduction Carbon nanopillars, tubes and wires have intrigued scientists ever since the first observation of carbon nanotubes in 1991 [1]. The most spectacular materials system is the fullerenes, but many other carbon based nanostructures have been presented, with a broad range of proposed applications in, e.g., sensors and electronic and photonic devices such as field emitting displays and data storage [2–5]. In most applications carbon nanostructures need to be arranged into a well-defined configurations [3]. This requires a fabrication method capable of producing arrays with well ordered high-density carbon nanopillar. While efforts to fabricate high-quality and aligned arrays of isolated carbon nanotubes have been successful, it is still a challenge to produce such arrays with uniform diameters and periodic arrangements to meet device requirements. Here a method is presented for direct deposition of carbon nanopillars within the pores of self-ordered porous alumina masks. The masks, prepared by anodic oxidation of high purity aluminum [6], present a hexagonal array of pores with somewhat tuneable pore diameters. The deposition is assisted by ion beam irradiation through a porous alumina template on a gold covered SiO 2 =Si substrate. Porous alumina have previously been used as a template for ion lithography [7–11]. Earlier works describe deposition of carbon nanopillars in the same dimension using porous alumina templates and depositing carbon using plasma enhanced chemical vapor deposition, chemical vapor deposition or pyrolisis [4,12–16]. These methods need of global heating is a problem. To ease the integration of such structures with electronic circuitry only small areas should be deposited at a low temperature. 2. Experimental Silicon with thermally grown SiO 2 was used as substrate. A thin layer of gold film (sub-10-nm thickness) was ARTICLE IN PRESS www.elsevier.com/locate/vacuum 0042-207X/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.vacuum.2007.05.002 Ã Corresponding author. Fax: +46 18 555736. E-mail address: jens.jensen@angstrom.uu.se (J. Jensen).