Semiconductor-metal phase transition in VO2 films synthesized on alpha-Al2O3 by oxygen-reactive deposition using a neodymium-doped yttrium aluminium garnet laser

Good-crystal-quality VO2 films have been synthesized on alpha-Al2O3 using a laser ablation technique. The epitaxial relationship between the film and substrate was examined with X-ray diffraction and Rutherford back-scatterin g spectroscopy-channelling techniques, and a systematic coherent stacking o f atoms twin formation found. As a function of temperature, the films under go a phase transition from a semiconductor to a metal at around 63 degrees C. The electrical resistance changes by 10(4) to 10(5) with a hysteresis wi dth of about 1 degrees C, and the optical transmission changes from 0.82 to 0.05 for 3.4 mu m infrared light.