High Sensitivity Graphene Temperature Sensor via Liquid Assist

Graphene was discovered in 2004 and regarded as a remarkable material cause by a lot of properties, such as optical, thermal, electrical and mechanical. Furthermore, it not only has ultra-high specific surface area (2630 m^2⁄g) but also rich in pore structure, so that may have the high sensitivity in gas adsorption. In this study, improving the temperature coefficient of resistance (TCR) of the graphene temperature sensor on the basis of graphene property which has high sensitivity in gas adsorption. And we reduce the internal contact resistance of graphene by transferring more than once. The few-layer graphene was grown by atmospheric pressure chemical vapor deposition using two kinds of catalysts, and 99.8% purity copper foils and 3M copper tapes. Graphene, then, transferred to the silicon wafer substrate. Finally, we discuss the effect of catalysts, liquids and transferring time. The experimental results indicate that annealing and deionized water adsorption are helpful to improve the consistency. However, the coefficient of variation in TCR will vary with the transferring time, and we find that a way to improve the reproducibility by transferring more than one time. Under the same measurement conditions, the coefficient of variation of samples which compare transferring three times (TCR=-0.317±0.056) with transferring one time (TCR=-0.380±0.126) will be decrease 16%. Moreover, the graphene grown by difference copper catalysts have similar TCR with difference of 0.95%.