Characterization of locally modified diamond surface using Kelvin probe force microscope Minoru Tachiki a,b, * , Yu Kaibara a,b , Yu Sumikawa a,b , Masatsugu Shigeno c , Hirohumi Kanazawa a,b , Tokishige Banno a,b , Kwang Soup Song a,b , Hitoshi Umezawa a,b , Hiroshi Kawarada a,b a CREST, Japan Science and Technology Corporation (JST), 5-3 Yonban, Chiyoda-ku, Tokyo 102-0081, Japan b School of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan c SII NanoTechnology Inc., Matsudo, Chiba 271-2222, Japan Received 16 September 2003; accepted for publication 28 February 2005 Available online 19 March 2005 Abstract The surface potential difference between an H-terminated surface and a locally oxidized diamond surface produced by an atomic force microprobe was investigated using a Kelvin probe force microscope. The potential of the H- terminated diamond surface was observed to be 0.1 V higher than that of the oxidized diamond surface. The surface potentialdifferencecanbeinterpretedintermsofthepositionsofthevacuumlevel,theFermilevel,andtheconduction and valence band edges, when negative electron affinity and p-type surface conduction are assumed on the H-termi- nated diamond surface. The surface dipole induced by the electronegativity differences between the surface atoms of the diamond affects the difference in the surface potential between the two surfaces. Ó 2005 Elsevier B.V. All rights reserved. Keywords: Diamond; Surface conduction; Hydrogen termination; AFM; KFM; Local oxidation; Surface charge 1. Introduction The properties of hydrogen-terminated (H- terminated) diamond surfaces contrast with those of oxygen-terminated (O-terminated) surfaces (Fig. 1(a)). Surface hydrogenation induces p-type surface conduction, even in undoped diamond, while O-terminated diamond is insulative [1–4]. The carrier density of this surface conductive layer 0039-6028/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.susc.2005.02.054 * Corresponding author. Present address: National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan. Tel./fax: +81352863391. E-mail address: tachiki@kaw.comm.waseda.ac.jp (M. Ta- chiki). Surface Science 581 (2005) 207–212 www.elsevier.com/locate/susc