CNT CANTILEVERS UNDER SOFT AC ACTUATION OF FREQUENCY NEAR HALF NATURAL FREQUENCY FOR BIO-SENSING APPLICATIONS

摘要

This paper deals with electrostatically actuated Carbon Nano-Tubes (CNT) cantilevers for bio-sensing applications. Four forces act on the CNT cantilever, namely electrostatic, elastostatic, van der Waals, and damping. The van der Waals forces are significant for values of 50 nm or lower of the gap between the CNT and the ground plate. As both forces electrostatic and van der Waals are nonlinear, and the CNT electrostatic actuation is given by AC voltage, the CNT undergoes nonlinear parametric dynamics. The method of multiple scales (MMS) is used to investigate the system under soft excitations and/or weak nonlinearities. The frequency-amplitude and frequency-phase behavior are reported. The CNT bio-sensor is to be used for mass detection applications.