Section 14. Wide band gap materials. II. Micro/nano carbon structures and nanotubes Carbon nano-structures containing nitrogen and hydrogen prepared by ion beam assisted deposition P. Paredez a , M.C. Marchi a , M.E.H. Maia da Costa a , C.A. Figueroa a , M.U. Kleinke a , C.T.M. Ribeiro b , J.C. Sa ´nchez-Lo ´pez c , T.C. Rojas c , F. Alvarez a, * a Instituto de Fı ´sica ‘Gleb Wataghin’, Universidade Estadual de Campinas, Unicamp, P.O. Box 6165 Campinas, SP 13083-970, Brazil b Instituto de Fı ´sica de Sa ˜o Carlos, Universidade de Sa ˜o Paulo, P.O. Box 369, Sa ˜o Carlos, SP, Brazil c Instituto de Ciencia de Materiales de Sevilla (CSIC – Univ. de Sevilla), Avda. Ame ´rico Vespucio, 49, 41092 Sevilla, Spain Available online 31 March 2006 Abstract In this paper, we report the synthesis and some properties of nano-structured carbon films grown on nanometric nickel particles at 700 °C by ion beam assisted deposition (IBAD). In situ photoelectron emission spectroscopy (XPS) reveals the presence of nitrogen in the carbon layer coating the nickel particles. Atomic force microscopy (AFM) displays regular dome-like structures with a mean width, height, and density of 170 nm, 22 nm, and 1.4 · 10 9 domes/cm 2 , respectively. Raman spectroscopy shows the characteristic frequen- cies associated with graphite and disordered structures. Disorder increases on increasing nitrogen content. High-resolution transmission electron microscopy (HRTEM) confirms the presence of multiwall well-organized graphite layers covering the nickel particles. The field emission properties of the structures are reported. Ó 2006 Elsevier B.V. All rights reserved. PACS: 81.05.Tp; 79.70.+q Keywords: Nano-clusters 1. Introduction Since the discovery of the carbon nanotubes by Iijima [1], carbon nano-structures have attracted much interest and many studies have been carried out. Carbon nano- structures like fullerenes, nanodomes, nanotubes, nano- onions, and nanohorns are interesting, mainly because of their possible applications [1,2]. In particular, nano-struc- tured carbon compounds are good candidates for field emission applications. Therefore, the electronic and struc- tural control of the material properties is mandatory to build efficient devices [3,4]. In recent years, several synthesizing routes were reported to produce doped fullerenes, nanotubes, and nanofibers [5]. Nitrogen, owning one extra valence electron than carbon, might act as a donor impurity when incorpo- rated into graphitic structures. Therefore, nitrogen doping is possible route to change the material conductivity [6]. From the structural point of view, N curls and bends the graphitic planes, promoting closed molecular shapes (ful- lerene-like) [5,7]. Atomic hydrogen etching has been exten- sively proved as an effective method in modifying the film nano-structures changing the carbon bonding in the graph- ite formation [8–10]. Finally, as it is well known, the pres- ence of transition metals catalyzes the formation of graphitic structures [11,12]. In this paper we report the synthesis and properties of CN x :H nano-structures growth by ion beam assisted depo- sition (IBAD) [6]. The effect of the simultaneous irradiation of the growing material with a nitrogen–hydrogen beam is studied. Structural analysis by AFM, HRTEM, and Raman scattering, were employed to characterize the 0022-3093/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2006.01.055 * Corresponding author. Tel.: +55 19 3788 5372; fax: +55 19 3788 5376. E-mail address: alvarez@ifi.unicamp.br (F. Alvarez). www.elsevier.com/locate/jnoncrysol Journal of Non-Crystalline Solids 352 (2006) 1303–1306