A robust analysis of the actuation of a carbon-nanotube-based nanoswitch with sidewall slip

Abstract

Carbon nanotubes (CNTs) have been widely used in a variety of research in nanoelectromechanical devices due to their excellent mechanical and electrical properties. This study focuses on the modeling and simulation of the actuation of a CNT-based nanoswitch. The CNT is modeled as a wire spanning a trench with displacement-induced tension and negligible bending stiffness. A distributed force is exerted on the nanotube due to the electrical potential difference between it and the trench electrode. This action causes the CNT to deflect toward the electrode. The phenomenon called snap-through occurs when the voltage exceeds a local maximum. The governing equation of the wire is a second-order nonlinear ordinary differential equation (ODE), which is solved by reducing it to a first-order ODE. After removing the singularity in the integral, we apply a numerical integration method. The use of this procedure gives complete results in the entire stable and unstable domains without any convergence issues. This is in contrast to the more traditional method of using finite differences directly to the second-order nonlinear equation, which requires an iterative technique and often fails to converge. The effect of slip in the section of the CNT lying on the substrate is also considered. Slip lowers the induced internal axial force, thereby decreasing the applied voltage needed for actuation.