Controlling the Temperature and Speed of the Phase Transition of VO2 Microcrystals

Joonseok Yoon, Howon Kim, Xian Chen, Nobumichi Tamura, Bongjin Simon Mun, Changwoo Park, Honglyoul Ju

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

We investigated the control of two important parameters of vanadium dioxide (VO2) 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 × 102 to 1.7 × 104 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 VO2, the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO2 microcrystals. Our findings not only enhance the understanding of VO2 intrinsic properties but also contribute to the development of innovative electronic devices.

Original languageEnglish
Pages (from-to)2280-2286
Number of pages7
JournalACS Applied Materials and Interfaces
Volume8
Issue number3
DOIs
Publication statusPublished - 2016 Jan 27

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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