Gao Feng, Qiu Yunfeng, Wei Shuai, Yang Huihui, Zhang Jia, Hu PingAn
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150080, People's Republic of China. MOE Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin 150080, People's Republic of China.
Nanotechnology. 2019 Oct 18;30(42):425501. doi: 10.1088/1361-6528/ab2d64. Epub 2019 Jun 27.
Highly sensitive strain sensors show great potential for use in wearable health monitoring, autonomous intelligent robots and biomimetic prosthetics. The current resistive strain sensors mainly work through piezoresistors. Here, the robust tunneling mechanism based nanoscale strain sensors with high sensitivity are reported. The strain sensors are fabricated from graphene nanoparticle film. The sensitivity of graphene nanoparticle strain sensors could be tunable through the modulation of tunneling type, suggesting a theoretical support in performance optimization of tunneling strain sensors. The output characterization indicates the direct tunneling (DT) and Fowler-Nordheim tunneling (FNT) are dominant for charge carrier transport in the low voltage and high voltage regions, respectively. It is found that gauge factors are ∼79 at low voltage of 0-4 V, and ∼110 at high voltage of 20-40 V, showing profound dependence on DT and FNT types. The strain sensor bearing 0.3% strain shows a great stability over 100 cycles at bias voltage of 1 V and 40 V, respectively. An integrated strain sensor array with 5 × 5 patterned graphene nanoparticle film on a polyethylene terephthalate substrate is fabricated and demonstrates great spatial strain distribution, guiding the design for flexible and transparent strain sensor e-skins.
高灵敏度应变传感器在可穿戴健康监测、自主智能机器人和仿生假肢方面展现出巨大的应用潜力。目前的电阻式应变传感器主要通过压阻器工作。在此，报道了基于具有高灵敏度的稳健隧穿机制的纳米级应变传感器。这些应变传感器由石墨烯纳米颗粒薄膜制成。石墨烯纳米颗粒应变传感器的灵敏度可通过隧穿类型的调制进行调节，这为隧穿应变传感器的性能优化提供了理论支持。输出特性表明，直接隧穿（DT）和福勒-诺德海姆隧穿（FNT）分别在低电压和高电压区域主导电荷载流子传输。研究发现，在0至4 V的低电压下，应变系数约为79，在20至40 V的高电压下，应变系数约为110，这表明其对DT和FNT类型有显著依赖性。承受0.3%应变的应变传感器在1 V和40 V的偏置电压下分别在100个循环中表现出极大的稳定性。在聚对苯二甲酸乙二醇酯基板上制备了具有5×5图案化石墨烯纳米颗粒薄膜的集成应变传感器阵列，该阵列展示出出色的空间应变分布，为柔性透明应变传感器电子皮肤的设计提供了指导。
