Vanadium dioxide single-crystal precipitates with controlled particle sizes were produced in an amorphous, fused SiO 2 host by the stoichiometric coimplantation of vanadium and oxygen ions and subsequent thermal processing. The effects of the vanadium dioxide nanocrystal size, nanocrystal morphology, and particle/host interactions on the VO 2 semiconductor-to-metal phase transition were characterized. VO 2 nanoparticles embedded in amorphous SiO 2 exhibit a sharp phase transition with a hysteresis that is up to 50°C in width - one of the largest values ever reported for this transition. The relative decrease in the optical transmission in the near-infrared region in going from the semiconducting to the metallic phase of VO 2 ranges from 20% to 35%. Both the hysteresis width and the transition temperature are correlated with the size of the precipitates. Doping the embedded VO 2 particles with ions such as titanium alters the characteristics of the phase transition, pointing the way to control the hysteresis behavior over a wide range of values and providing insight into the operative physical mechanisms.
ASJC Scopus subject areas
- Physics and Astronomy(all)