Vogl Lilian M, Schweizer Peter, Denninger Peter, Richter Gunther, Spiecker Erdmann
Institute of Micro- and Nanostructure Research (IMN), Center for Nanoanalysis and Electron Microscopy (CENEM), Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany.
ACS Nano. 2022 Nov 22;16(11):18110-18118. doi: 10.1021/acsnano.2c04848. Epub 2022 Oct 25.
Modern devices based on modular designs require versatile and universal sensor components which provide an efficient, sensitive, and compact measurement unit. To improve the space capacity of devices, miniaturized building elements are needed, which implies a turning away from conventional microcantilevers toward nanoscale cantilevers. Nanowires can be seen as high-quality resonators and offer the opportunity to create sensing devices on small scales. To use such a one-dimensional nanostructure as a resonant cantilever, a precise characterization based on the fundamental properties is needed. We present a correlative electron and light microscopy approach to characterize the pressure and environment sensing capabilities of single nanowires by analyzing their resonance behavior . The high vacuum in electron microscopes enables the characterization of the intrinsic vibrational properties and the maximum quality factor. To analyze the damping effect caused by the interaction of the gas molecules with the excited nanowire, the resonance measurements have been performed under non-high-vacuum conditions. For this purpose, single nanowires are mounted in a specifically designed compact gas chamber underneath the light microscope, which enables direct observation of the resonance behavior and evaluation of the quality factor with dependence of the applied gas atmosphere (He, N, Ar, Air) and pressure level. By using the resonance vibration, we demonstrate the pressure sensing capability of a single nanowire and examine the molar mass of the surrounding atmosphere. Together this shows that even single nanowires can be utilized as versatile nanoscale gas sensors.
基于模块化设计的现代设备需要多功能且通用的传感器组件，以提供高效、灵敏且紧凑的测量单元。为了提高设备的空间容量，需要小型化的构建元件，这意味着要从传统的微悬臂梁转向纳米级悬臂梁。纳米线可被视为高质量的谐振器，并提供了在小尺度上制造传感设备的机会。要将这种一维纳米结构用作谐振悬臂梁，需要基于其基本特性进行精确表征。我们提出了一种关联电子显微镜和光学显微镜的方法，通过分析单根纳米线的共振行为来表征其压力和环境传感能力。电子显微镜中的高真空环境能够对其固有振动特性和最大品质因数进行表征。为了分析气体分子与受激纳米线相互作用所引起的阻尼效应，在非高真空条件下进行了共振测量。为此，将单根纳米线安装在光学显微镜下方专门设计的紧凑型气室内，这使得能够直接观察共振行为，并根据所施加的气体气氛（氦气、氮气、氩气、空气）和压力水平评估品质因数。通过利用共振振动，我们展示了单根纳米线的压力传感能力，并研究了周围大气的摩尔质量。综合来看，这表明即使是单根纳米线也可被用作多功能的纳米级气体传感器。
