Electromechanical response of materials is a key property for various applications ranging from actuators to sophisticated nanoelectromechanical systems. Here electromechanical properties of the single-layer graphene transferred onto SiO2 calibration grating substrates is studied via piezoresponse force microscopy and confocal Raman spectroscopy. The correlation of mechanical strains in graphene layer with the substrate morphology is established via Raman mapping. Apparent vertical piezoresponse from the single-layer graphene supported by underlying SiO2 structure is observed by piezoresponse force microscopy. The calculated vertical piezocoefficient is about 1.4 nm V−1, that is, much higher than that of the conventional piezoelectric materials such as lead zirconate titanate and comparable to that of relaxor single crystals. The observed piezoresponse and achieved strain in graphene are associated with the chemical interaction of graphene's carbon atoms with the oxygen from underlying SiO2. The results provide a basis for future applications of graphene layers for sensing, actuating and energy harvesting.
展开▼
机译：材料的机电响应是从执行器到复杂的纳米机电系统的各种应用的关键特性。在这里，通过压电响应力显微镜和共聚焦拉曼光谱研究了转移到SiO2校准光栅基板上的单层石墨烯的机电性能。石墨烯层中的机械应变与衬底形态之间的关系是通过拉曼映射建立的。通过压电响应力显微镜观察到了由底层SiO2结构支撑的单层石墨烯的明显垂直压电响应。计算得到的垂直压电系数约为1.4 nm V -1 ，这比锆钛酸铅等常规压电材料要高得多，与弛豫单晶相当。在石墨烯中观察到的压电响应和获得的应变与石墨烯的碳原子与来自下面的SiO2的氧的化学相互作用有关。结果为石墨烯层在传感，致动和能量收集方面的未来应用提供了基础。
展开▼
