We examined the correlation between thickness of an epitaxial VO2 phase grown on a TiO2 (0 0 1) substrate by the excimer-laser-assisted metal organic deposition (ELAMOD) process and the metal-insulator transition (MIT) property of it. The abrupt and hysteretic MIT was observed for the epitaxial films (thickness: t >= 6 nm), and the epitaxial film (t <= 4 nm) showed semiconductor behavior. When an amorphous VOx layer was prepared on the ultrathin epitaxial phase (t <= 4 nm) by the ELAMOD, a non-hysteretic MIT was successfully observed. The non-hysteretic MIT was found to be owing to roughened interface between the epitaxial phase and the amorphous phase, where there would be a number of structural defects. (C) 2010 Elsevier B.V. All rights reserved.