Hydrogen-Induced Morphotropic Phase Transformation of Single-Crystalline Vanadium Dioxide Nanobeams

Title
Hydrogen-Induced Morphotropic Phase Transformation of Single-Crystalline Vanadium Dioxide Nanobeams
Authors
허윤석
Keywords
Morphotropic transformation, vanadium dioxide, metal?insulator transition, hydrogen annealing, reduction, compositional variation
Issue Date
2013
Publisher
NANO LETTERS
Series/Report no.
NANO LETTERS; vol.13 no.4 startpage 1822 endpage 1828
Abstract
We report a morphotropic phase transformation in vanadium dioxide (VO2) nanobeams annealed in a high-pressure hydrogen gas, which leads to the stabilization of metallic phases. Structural analyses show that the annealed VO2 nanobeams are hexagonal-close-packed structures with roughened surfaces at room temperature, unlike as-grown VO2 nanobeams with the monoclinic structure and with clean surfaces. Quantitative chemical examination reveals that the hydrogen significantly reduces oxygen in the nanobeams with characteristic nonlinear reduction kinetics which depend on the annealing time. Surprisingly, the work function and the electrical resistance of the reduced nanobeams follow a similar trend to the compositional variation due mainly to the oxygen-deficiencyrelated defects formed at the roughened surfaces. The electronic transport characteristics indicate that the reduced nanobeams are metallic over a large range of temperatures (room temperature to 383 K). Our results demonstrate the interplay between oxygen deficiency and structural/electronic phase transitions, with implications for engineering electronic properties in vanadium oxide systems.
URI
http://dspace.inha.ac.kr/handle/10505/32605
ISSN
1530-6984
Appears in Collections:
College of Engineering(공과대학) > Biotechnology (생명공학) > Local Access Journal, Report (생명공학 논문, 보고서)

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