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Title: Controlling the Temperature and Speed of the Phase Transition of VO 2 Microcrystals

Here, we investigated the control of two important parameters of vanadium dioxide (VO 2 ) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ~70 to ~1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition by using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10 2 to 1.7 × 10 4 μm/s as the width decreases from ~50 to ~2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO 2 , the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO 2 microcrystals. These findings not only enhance the understanding of VO 2 intrinsic properties but also contribute to the development of innovative electronic devices.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Yonsei Univ., Seoul (Republic of Korea). Dept. of Physics
  2. Hong Kong Univ., of Science and Technology (China). Dept. of Mechanical and Aerospace Engineering
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source
  4. Gwangju Inst. of Science and Technology (Korea, Republic of). Dept. of Physics and Photon Science, Ertl Center for Electrochemistry and Catalysis
  5. Hanbat National Univ., Daejeon (Republic of Korea). Division of Applied Chemistry and Biotechnology; Advanced Nano Products, Sejong (Republic of Korea)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; high-speed resistance measurement; metal−insulator transition; microcrystal; phase transition speed; phase transition temperature; size effect; vanadium dioxide
OSTI Identifier:
1379049