High-performance flexible metal-on-silicon thermocouple

• Main Authors: Daniel Assumpcao, Shailabh Kumar, Vinayak Narasimhan, Jongho Lee, Hyuck Choo
• Format: Article
• Language: English
• Published: Nature Publishing Group 2018-09-01
• Series: Scientific Reports
• Subjects: Thin Film Thermocouples; Seebeck Coefficient; Temporal Resolution Sensors; Costly Fabrication Processes; Silicone Arm
• Online Access: https://doi.org/10.1038/s41598-018-32169-9

Abstract We have demonstrated metal-on-silicon thermocouples with a noticeably high Seebeck coefficient and an excellent temperature-sensing resolution. Fabrication of the thermocouples involved only simple photolithography and metal-liftoff procedures on a silicon substrate. The experimentally measured Seebeck coefficient of our thermocouple was 9.17 × 10−4 V/°K, which is 30 times larger than those reported for standard metal thin-film thermocouples and comparable to the values of alloy-based thin-film thermocouples that require sophisticated and costly fabrication processes. The temperature-voltage measurements between 20 to 80 °C were highly linear with a linearity coefficient of 1, and the experimentally demonstrated temperature-sensing resolution was 0.01 °K which could be further improved up to a theoretical limit of 0.00055 °K. Finally, we applied this approach to demonstrate a flexible metal-on-silicon thermocouple with enhanced thermal sensitivity. The outstanding performance of our thermocouple combined with an extremely thin profile, bending flexibility, and simple, highly-compatible fabrication will proliferate its use in diverse applications such as micro-/nanoscale biometrics, energy management, and nanoscale thermography.