Solid Phase Crystallization of Vanadium Dioxide Thin Films and Characterization Through Scanning Electron Microscopy

• Main Author: Rivera, Felipe
• Format: Others
• Published: BYU ScholarsArchive 2007
• Subjects: Vanadium Dioxide; scanning electron microscopy; SEM; orientation imaging microscopy; OIM; electron back-scattered diffraction; EBSD; Kikuchi patterns; solid phase crystallization; Astrophysics and Astronomy; Physics
• Online Access: https://scholarsarchive.byu.edu/etd/1267; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2266&context=etd

Crystalline films of vanadium dioxide were obtained through thermal annealing of amorphous vanadium dioxide thin films sputtered on silicon dioxide. An annealing process was found that yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. Orientation Imaging Microscopy (OIM) was used to characterize and study the phase and the orientation of the vanadium dioxide crystals obtained, as well as to diferentiate them from other vanadium oxide stoichiometries that may have formed during the annealing process. There was no evidence of any other vanadium oxides present in the prepared samples. Indexing of the crystals for the orientation study was performed with the Kikuchi patterns for the tetragonal phase of vanadium dioxide, since it was observed that the Kikuchi patterns for the monoclinic and tetragonal phases of vanadium dioxide are indistinguishable by OIM. It was found that a particle size of 100 nm was in the lower limit of particles that could be reliably characterized with this technique. It was also found that all VO2 crystals large enough to be indexed by OIM had a preferred orientation with the C axis of the tetragonal phase parallel to the plane of the specimen.