Presentation Information
[2I10]Tuning metal-insulator transition temperature of VO2 thin film via substrate surface engineering
*Hiroki Miyashita1, Sharad Sunil Mane2, Azusa N Hattori2, Seiji Nakashima1, Hironori Fujisawa1, Ai I Osaka1,2 (1. Graduate School of Engineering, University of Hyogo, 2. SANKEN, Osaka University)
Vanadium dioxide (VO2) exhibits a metal-insulator transition (MIT) near 68 °C, accompanied by a drastic change in resistivity. In this study, we propose nanoscale engineering of substrate surface roughness as a strategy to modulate the MIT temperature of VO2 thin films and systematically investigate its effect. VO2 films were grown on Si(100) substrates with root-mean-square roughness values of 1.3 nm and 2.5 nm, showing MIT temperatures of 63.3°C and 62.4°C, respectively. The corresponding grain sizes were 17.4 nm and 16.5 nm. These results indicate that a rougher surface leads to reduced grain size and a lower MIT temperature. This can be attributed to the tendency of the insulating monoclinic phase to develop structural disorder at grain boundaries, promoting local transformation to a tetragonal metallic-like structure and facilitating the transition. These findings highlight nanoscale surface morphology control as a promising approach for tuning the MIT temperature.