Crystalline structure of TiC ultrathin layers formed on highly oriented pyrolytic graphite by chemical reaction from Ti/graphite system

We have investigated the atomic-scale reaction between a Ti thin layer and highly oriented pyrolytic graphite (HOPG) mainly by scanning tunneling microscopy. A deposited Ti layer shows an epitaxial orientation structure on a HOPG substrate even in room-temperature deposition, while the bonding between Ti and HOPG is very weak. The chemical reaction between Ti and HOPG takes place, and epitaxial TiC domains on HOPG are formed for annealing at above 600 degrees C. The TiC domains shows a smooth surface corresponding to the TiC(111) plane after annealing at 700 degrees C. The formation of TiC(001) facets and significant surface roughening of not only TiC but also HOPG substrates are observed for annealing at as high as 900 degrees C. (C) 2016 The Japan Society of Applied Physics