VO2 film temperature dynamics at low-frequency current self-oscillations

• Published in: Journal of applied physics 2018-02, Vol.123 (7)
• Main Authors: Bortnikov, S. G., Aliev, V. Sh, Badmaeva, I. A., Mzhelskiy, I. V.
• Format: Article
• Language: English
• Subjects: Applied physics; Dielectric relaxation; Insulators; Oscillations; Phase transitions; Temperature distribution; Vanadium dioxide; Vanadium oxides
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.5010971

Low-frequency (∼2 Hz) current self-oscillations were first obtained in a millimeter-sized two-terminal planar device with a vanadium dioxide (VO2) film. The film temperature distribution dynamics was investigated within one oscillation period. It was established that the formation and disappearance of a conductive channel occur in a film in less than 60 ms with oscillation period 560 ms. The experimentally observed temperature in the channel region reached 413 K, being understated due to a low infrared microscope performance (integration time 10 ms). The VO2 film temperature distribution dynamics was simulated by solving a 2D problem of the electric current flow and heat transfer in the film. The calculation showed that the thermally initiated resistance switching in the film occurs in less than 4 ms at a channel temperature reaching ∼1000 K. The experimental results and simulation are consistent with the current self-oscillation mechanism based on the current pinching and dielectric relaxation in the VO2 film at the metal-insulator phase transition.