Switching Properties and Phase Transition Mechanism of Mo6+-Doped Vanadium Dioxide Thin Films
Chin. Phys. Lett. 2003, 20 (1):
Using V2O5 and MoO3 powders as precursors, a novel preparation method, i.e., the so-called inorganic sol-gel, is developed to synthesize Mo6+-doped vanadium dioxide (VO2) thin films. The structure, valence state, phase transition temperature and magnitude of resistivity change are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and the four point equipment. The results show that the main chemical composition of doped thin films was VO2, the structure of MoO3 in doped thin films did not change, and the phase transition temperature of doped thin films was obviously lowered with the increasing MoO3 doped concentration, but the magnitude of resistivity change was also decreased. However, so long as MoO3 doped concentration was not more than 5wt.%, the magnitude of resistivity change of doped thin films still reached more 2 orders. The analysis show that MoO3 dissolved in crystal structure of VO2 formed the donor defect MOxv and then reduced the forbidden-band width, which lowered the phase transition temperature. Consequently it was widened applications of the VO2 thin films.