频率可调碳纳米管谐振器的TEM原位构建

In-situ TEM construction of tunable carbon nanotube resonators

提出了1种基于电子束致沉积无定形碳技术的可控调节碳纳米管谐振器频率的新方法,利用原位透射电镜技术,通过控制电子束斑的位置、大小和沉积时间,精确控制所沉积无定形碳在碳纳米管悬臂梁上的位置和质量。实验结果表明,通过在碳纳米管悬臂梁顶端沉积碳纳米颗粒可大幅度调节碳纳米管的共振频率,实现谐振频率的粗调模式,调节幅度可超过50%;若将沉积位置远离碳纳米管悬臂梁顶端,则可实现碳纳米管谐振器共振频率的精细调节,调节精度可达到2%。以实验探讨了Rayleigh-Ritz理论对于计算碳纳米管谐振器称量质量的适用性,证明所称量的纳米颗粒的质量越小,计算结果的准确性越高。

To tune the frequency of carbon nanotube （CNT） resonators in a highly controlled manner, anovel approach based on e-lectron beam induced deposition of amorphous carbon was proposed. Due to the extremely tiny size of CNTs and the difficulty in controlling the CNT resonator frequency, in-situ transmission electron microscopy was utilized to precisely control the location and mass of the deposited carbon particles along the CNT cantilever by choosing the sites and spot size of the electron beam, as well as the deposition time. Experimental results demonstrate that coarse frequency tuning can be achieved by depositing amor-phous carbon nanoparticles at the tip of the carbon nano tube cantilever, which leads to a large frequency shift range, exceeding 50%. If the carbon deposition is controlled at the positions far away from the CNT tip, tuning precision can be greatly improved, achieving fine tuning of frequency with a precision of 2%. Furthermore, the validity of the Rayleigh-Ritz theory on the mass cal-culation of this CNT nanobalance is experimentally addressed, and it is verified that the lower measured mass leads to the better accuracy of the calculations.