Mechanical Design of Graphene Nanoribbon Compliant Mechanisms for Electrostatic Discharge
- Author(s): Jones, Talmage
- Advisor(s): Hopkins, Jonathan
- et al.
The purpose of this research is to investigate the design of an electrostatic discharge protection device made of single-layer graphene nanoribbons. The device is meant to trigger electrostatic discharge at a target voltage of 1.5V. Other design requirements include the minimization of parasitic capacitance, electrical response time and mechanical response time. The device is designed to discharge static electricity by being pulled to ground through electrostatic forces, then making contact with ground before returning to its original position. Previous designs experienced repeatability issues due to a lack of securing the ribbon and mechanical failure due to high stresses at the boundary conditions. New designs are presented and optimized to maintain a high effective spring constant for the device while reducing stress during electrostatic pull-in. A single-degree-of-freedom model is used in conjunction with the Bernoulli-Euler beam equations and Castigliano’s method to guide the design process. Multi-degree-of-freedom and finite element models are used to validate the predicted pull-in behavior of the new devices and to explore how stresses and reaction forces might affect the reliability. A residual PMMA layer that results from the fabrication process is also incorporated into the finite element model. Molecular dynamics simulations are performed to further explore the behavior of graphene nanoribbons under electrostatic pull-in and to check the accuracy of the finite element approach. The fabrication process is explained and experimental results for the new devices are reported.