Channelling studies on the lattice location of B atoms in graphite

in order to obtain information on the lattice location of B atoms in graphite, channelling experiments have been performed at room temperature with a proton beam of an energy of 0.65-0.77 MeV for the <0 0 0 1> axial channel in highly oriented pyrolytic graphite (HOPG) crystals doped with 0.32 at.% B. The B atoms are detected by measuring alpha-particles which are emitted as a result of a nuclear reaction B-11(p,alpha)alphaalpha. It is clearly demonstrated that most of B atoms are shadowed behind the <0 0 0 1> C atomic rows. Taking account of the already reported experimental results on a change of lattice parameters by B-doping, it is concluded that most of B atoms are located at substitutional sites. It is also observed that B-doping introduces lattice strain on the c-plane. In addition, the presence of a small portion of interstitial B atoms is suggested. (C) 2004 Elsevier B.V. All rights reserved.