[3Cp01-06] ISSP2024 pre-session - A new dawn of sputtering and plasma processes: Sputtering and Plasma Processes Division's Session

[3Cp01] Emerging technologies utilizing vanadium dioxide films with insulator metal transition - Smart windows for energy savings and self-sustained electrical oscillations -

*Kunio Okimura¹ (1. School of Engineering, Tokai University)

Vanadium dioxide (VO₂) is known as a phase transition compound which shows insulator-metal transition (IMT) with its structural phase transition (SPT) from low-temperature monoclinic phase (P2₁/c) to high-temperature tetragonal phase (P4₂/mnm) at 68 °C. The abrupt resistivity change over 4 orders of magnitude is realized even in thin films with thickness of around 15 nm. In this presentation, we introduce applications of VO₂ films to energy-saving smart windows and oscillation phenomenon of voltage-induced IMT. We tried to fabricate VO₂-coated glasses for smart windows where infrared-light (IR) incidence is automatically controlled to avoid room temperature rise in hot summer. As performance index, we realized the solar modulation ability (ΔT_sol) higher than 15% which is approaching top-ranking value. In addition, we fabricated planer VO₂ device where Ti/Au electrodes are metallized on the VO₂ film grown on Al₂O₃ (001) substrate. It will be shown that the self-sustained oscillations were successfully triggered by the DC voltage addition to this device. We also reported coupled oscillations by connecting two single oscillators through capacitance.