Puneetha Peddathimula, Mallem Siva Pratap Reddy, Lee Young-Woong, Shim Jaesool
School of Mechanical Engineering, Yeungnam University, Gyeongsan 38541, South Korea.
School of Electronics Engineering, Kyungpook National University, Daegu 41566, South Korea.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36660-36669. doi: 10.1021/acsami.0c06534. Epub 2020 Jul 29.
Using simple graphene transfer and the laser lift-off process for a non-centrosymmetric GaN layer on a flexible polydimethylsiloxane (PDMS) substrate, the piezotronic effect by strain-induced current-voltage measurements at the two end points is studied. By inducing compressive strain on the flexible graphene/GaN/PDMS sensor, the Schottky barrier between the graphene and GaN/PDMS heterojunction can be electro-mechanically modulated by the piezotronic effect. It is observed that the flexible graphene/GaN/PDMS sensor is sensitive to various applied compressive and tensile strains in the positive/negative bias scans. The sensor is extremely sensitive to a compressive strain of -0.1% with a gauge factor of 13.48, which is 3.7 times higher than that of a standard metal strain gauge. Furthermore, the sharp response of the flexible graphene/GaN/PDMS sensor under the -0.1% compressive strain is also investigated. The results of this study herald the development of commercially viable large-scale flexible/wearable strain sensors based on the strain-controlled piezotronic effect in future investigations.
利用简单的石墨烯转移和激光剥离工艺，在柔性聚二甲基硅氧烷（PDMS）衬底上制备非中心对称氮化镓（GaN）层，通过在两个端点处进行应变诱导电流-电压测量来研究压电子效应。通过在柔性石墨烯/GaN/PDMS传感器上施加压缩应变，石墨烯与GaN/PDMS异质结之间的肖特基势垒可通过压电子效应进行机电调制。研究发现，在正向/负向偏置扫描中，柔性石墨烯/GaN/PDMS传感器对各种施加的压缩和拉伸应变敏感。该传感器对-0.1%的压缩应变极为敏感，应变系数为13.48，比标准金属应变计高3.7倍。此外，还研究了柔性石墨烯/GaN/PDMS传感器在-0.1%压缩应变下的快速响应。本研究结果预示着在未来的研究中，基于应变控制压电子效应的具有商业可行性的大规模柔性/可穿戴应变传感器将得到发展。
