Efficient cooling systems are urgently needed because of increasing power density of electronic devices per one semiconductor chip as high as hundreds of W/cm². Recently, we demonstrated that degassing water leads to generation of a water vapor microbubble and subsequent rapid flow under localized heating. In addition, the bubble was found to oscillate at several hundred kHz. In this study, we investigate the dependence of the size and oscillation frequency of the microbubble on the concentration of incompressible gas dissolved in water by focusing a CW laser on the β-FeSi₂ thin film. We found that lower concentration of incompressible gas dissolved in water leaded to smaller size and higher oscillation frequency of a bubble. Furthermore, bubble whose radius is larger than 7.5 μm showed no oscillation in our system. Our work gives a new understanding about the bubble oscillation mechanism and will develop the technique for a novel cooling system using microfluidics.

Date Published: 2 March 2020
PDF: 6 pages
Proc. SPIE 11268, Laser-based Micro- and Nanoprocessing XIV, 1126807 (2 March 2020); doi: 10.1117/12.2545293

Published in SPIE Proceedings Vol. 11268:
Laser-based Micro- and Nanoprocessing XIV
Udo Klotzbach; Akira Watanabe; Rainer Kling, Editor(s)