Piezoresistive effect observed in flexible amorphous carbon films

• Published in: Journal of physics. D, Applied physics Vol. 51; no. 17; pp. 175304 - 175309
• Main Authors: Wang, B, Jiang, Y C, Zhao, R, Liu, G Z, He, A P, Gao, J
• Format: Journal Article
• Language: English
• Published: IOP Publishing 10.04.2018
• Subjects: amorphous carbon; flexible materials; piezoresistive effect
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/1361-6463/aab75c

Amorphous carbon (a-C) films, deposited on Si substrates at 500 °C, were transferred onto flexible polyethylene (PE) substrates by a lift-off method, which overcomes the limit of deposition temperature. After transferring, a-C films exhibited a large piezoresistive effect. Such flexible samples could detect the change of bending angle by attaching them onto Cu foils. The ratio of the bending and non-bending resistances reaches as large as ~27.8, which indicates a potential application as a pressure sensor. Also, the a-C/PE sample revealed an enhanced sensitivity to gas pressure compared with the a-C/Si one. By controlling the bending angle, the sensitivity range can be tuned to shift to a low- or high-pressure region. The fatigue test shows a less than 1% change in resistance after 10 000 bending cycles. Our work provides a route to prepare the flexible and piezoresistive carbon-based devices with high sensitivity, controllable pressure-sensing and high stability.