Structural mapping of single-crystal VO 2 microrods through metal-to-insulator phase transition
- PDF / 3,632,560 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 39 Downloads / 184 Views
Structural mapping of single-crystal VO2 microrods through metal-to-insulator phase transition Chunzi Zhang1,* , Ozan Gunes1, Cyril Koughia1, Jingyang Peng2, Shie-Jie Wen3, Rick Wong3, Q. Yang4, and S. O. Kasap1 1
Department of Electrical and Computer Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada 2 School of Mechatronic Systems Engineering, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A1S6, Canada 3 Cisco Systems Inc., San Jose, CA 95134, USA 4 Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada
Received: 7 July 2020
ABSTRACT
Accepted: 23 August 2020
The domain structure of two selected single-crystal VO2 microrods (MRs) with different morphologies was mapped by pixelated Raman imaging through the metal-to-insulator transition (MIT) during heating and cooling schedules through 68 °C. The results show that MIT does not occur simultaneously and uniformly throughout the whole MR, and instead, it proceeds through alternating metal–insulator domains. Each structural domain possesses its own MIT transition temperature and hysteresis width. The variations in MIT characteristics among different domains of a single MR are probably ascribed to structural nonuniformity. The observed overall MIT transition and hysteresis width of a given VO2 single-crystal MR is an aggregate manifestation of the MIT properties of domains within the crystal.
Ó
Springer Science+Business
Media, LLC, part of Springer Nature 2020
Handling Editor: M. Grant Norton.
Address correspondence to E-mail: [email protected]
https://doi.org/10.1007/s10853-020-05297-9
J Mater Sci
GRAPHIC ABSTRACT
Introduction and objectives Vanadium dioxide (VO2) has been widely studied for applications in optical switches, sensors, smart windows, and optical memory devices [1–6]. Most of its applications rely on VO2’s insulator-to-metal (or metal-to-insulator) phase transition (IMT, MIT) in which VO2 undergoes a phase transition from a semiconducting (insulator) phase to a metallic phase around 68 °C as it is heated from below to above this temperature [7]. The phase transition as observed through the properties of VO2 is reversible but evinces hysteresis with a temperature with DT. During this phase transition, the crystal structure of VO2 transforms abruptly from a low-temperature monoclinic phase to a high-temperature tetragonal phase [8]. Recently, VO2 thin films have been extensively studied to achieve enhanced optical and electrical properties [9, 10], higher switching efficiencies [11, 12], lower transition temperatures [13–16], higher transition temperatures [17, 18], larger-scale growth [19], novel properties, and better device design [20–22], and, of course, to have a deeper understanding of the MIT mechanism [23–25]. Nevertheless, hitherto the MIT mechanism remains unclear, which limits new potential applications.
Single-crystal VO2 nanostructures, including nanowires, nanobeams, nanorods, have attracted great attention for thei
Data Loading...
