Seminar: Electro-Optics and Microelectronics Seminar

ECE Women Community

Snap-Through bi-stability in carbon nanotube resonators

Date: January,17,2022 Start Time: 14:30 - 15:30 Add to:
Lecturer: Sharon Rechnitz
Affiliations: The Andrew and Erna Viterbi Faculty of Electrical & Computer Engineering

Bi-stable micro electro mechanical systems (MEMS) serve as the underlying mechanism for many practical applications such as switches, actuators, sensors, and memory elements. Reducing the dimensions of the device to the nano scale improves its performance and enables observation of quantum effects that are not accessible via MEMS devices. While suspended CNT devices are ideal for sensing and quantum research, a bi-stable nanotube resonator has never been realized.

In this research, we report a new class of CNT resonators in which the nanotube is buckled upward. This initial configuration enables a static out-of-plane movement with unique resonance frequency signature. We show that a small upward buckling yields record electrical frequency tunability, whereas larger buckling can achieve Euler-Bernoulli (EB) bi-stability, the smallest mechanical resonator with two stable configurations to date. Since the electronic properties of a CNT are so strongly affected by its mechanics, we even observe a DC signature of the ST transition in simple conductance measurements. We believe that this new class of CNT resonators will open new avenues for realizing nano-sensors, mechanical memory elements and mechanical parametric amplifiers.

We develop a three-dimensional theoretical analysis of the system, and present a thorough theoretical investigation of the system. The theory reveals significant nonlinear coupling between the in-plane and out-of-plane static and dynamic modes of motion, and a unique three-dimensional EB snap-through transition. In addition, the unique nonlinear mode coupling of these devices facilitates the experimental verification of the fluctuation broadening theory as the primary cause for mechanical dissipation and low quality factor in CNT resonators at room temperature. Understanding this mechanism opens the possibility for improved dissipation control in nano-mechanical resonators and improves general understanding of dissipation mechanisms at the nano scale.

 

PhD candidate under the supervision of Prof. Yuval Yaish.

 

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