The voltage-dependent manipulation of few-layer graphene with a scanning tunneling microscopy tip
The voltage-dependent manipulation of few-layer graphene with a scanning tunneling microscopy tip
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DOI：
10.1016/j.carbon.2020.03.046
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发表时间：
2020-08-15
期刊：
影响因子：
10.9
通讯作者：
Cobley，Richard J.
中科院分区：
文献类型：
--
作者：
Alyobi，Mona M.;Barnett，Chris J.;Cobley，Richard J.
应变和变形改变了石墨烯的电子性质，提供了控制其输运行为的可能性。扫描隧道显微镜的尖端是一种理想的工具，可以在局部机械扰动系统的同时测量电子响应。在这里，我们拉伸支撑在SiO2衬底上并悬浮在空隙上的多层和多层石墨烯膜。一种自动化的方法，收回方法稳定地跟踪石墨烯偏转滞后曲线数百次跨越四个样品，测量电压依赖性拉伸，从中我们提取的滞后宽度。使用力平衡模型，我们能够再现电压依赖性滞后石墨烯延伸行为。我们直接观察到一个电压依赖的相互作用，静电力占主导地位，在高电压和货车范德华力在低电压。每种力的相对贡献取决于石墨烯和隧穿电阻，从而引起样品之间观察到的不同的电压依赖性行为。了解这些力的电压依赖性会影响2D材料的扫描探针测量，并为振荡石墨烯器件设计提供信息，其中类似的力从腔体的侧壁作用，从而导致分层2D系统的应变工程。
Strain and deformation alter the electronic properties of graphene, offering the possibility to control its transport behavior. The tip of a scanning tunneling microscope is an ideal tool to mechanically perturb the system locally while simultaneously measuring the electronic response. Here we stretch few- and multi-layer graphene membranes supported on SiO2substrates and suspended over voids. An automated approach-retraction method stably traces the graphene deflection hysteresis curve hundreds of times across four samples, measuring the voltage-dependent stretching, from which we extract the hysteresis width. Using a force-balance model, we are able to reproduce the voltage-dependent hysteretic graphene extension behavior. We directly observe a voltage-dependent interplay where electrostatic forces dominate at high voltage and van der Waals forces at low voltage. The relative contribution of each force is dependent on the graphene and tunneling resistance, giving rise to different observed voltage-dependent behavior between samples. Understanding the voltage dependence of these forces impacts scanning probe measurement of 2D materials and informs oscillating graphene device design where similar forces act from the side walls of cavities, leading towards strain engineering of layered 2D systems.