Xiao Xing, Fan Shang-Chun, Li Cheng
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China.
Key Laboratory of Quantum Sensing Technology (Beihang University), Ministry of Industry and Information Technology, Beijing 100191, China.
Micromachines (Basel). 2021 Feb 12;12(2):189. doi: 10.3390/mi12020189.
Edge mode could disturb the ultra-subtle mass detection for graphene resonators. Herein, classical molecular dynamics simulations are performed to investigate the effect of edge mode on mass sensing for a doubly clamped strained graphene resonator. Compared with the fundamental mode, the localized vibration of edge mode shows a lower frequency with a constant frequency gap of 32.6 GHz, despite the mutable inner stress ranging from 10 to 50 GPa. Furthermore, the resonant frequency of edge mode is found to be insensitive to centrally located adsorbed mass, while the frequency of the fundamental mode decreases linearly with increasing adsorbates. Thus, a mass determination method using the difference of these two modes is proposed to reduce interferences for robust mass measurement. Moreover, molecular dynamics simulations demonstrate that a stronger prestress or a higher width-length ratio of about 0.8 could increase the low-quality factor induced by edge mode, thus improving the performance in mass sensing for graphene resonators.
边缘模式可能会干扰石墨烯谐振器的超精细质量检测。在此，进行经典分子动力学模拟以研究边缘模式对双端夹紧应变石墨烯谐振器质量传感的影响。与基模相比，尽管内部应力在10至50 GPa之间变化，但边缘模式的局部振动频率较低，频率间隙恒定为32.6 GHz。此外，发现边缘模式的共振频率对位于中心的吸附质量不敏感，而基模的频率随吸附物增加呈线性下降。因此，提出了一种利用这两种模式差异的质量测定方法，以减少干扰，实现可靠的质量测量。此外，分子动力学模拟表明，更强的预应力或约0.8的更高宽长比可以增加边缘模式引起的低品质因数，从而提高石墨烯谐振器的质量传感性能。
