DC Signature of snap-through bi-stability in carbon nanotube resonators

TL;DR

This paper investigates the DC conductance change in carbon nanotube resonators during snap-through buckling, linking it to capacitance variation and enabling advanced device characterization and potential applications in RF switches and memory devices.

Contribution

It introduces the analysis of conductance jumps in CNT resonators during snap-through, connecting mechanical transitions to electrical properties with precise shape prediction.

Findings

Conductance change is due to capacitance variation, not tension.

Exact shape prediction enables quantitative analysis.

Hysteresis indicates potential for static latching in devices.

Abstract

Bi-stable arched beams exhibiting Euler-Bernoulli snap-through buckling are vastly used as electronic devices in various applications, such as memory devices, energy harvesters, sensors, and actuators. Recently, we reported the realization of the smallest bi-stable resonator to date, in the form of a buckled suspended carbon nanotube (CNT), which exhibits a unique three-dimensional snap-through transition and an extremely large change in frequency as a result. In this article, we address a unique characteristic of these devices, in which a significant change in the DC conductance is also observed at the mechanical snap-through transition. After verifying that the change in the CNT tension due to the "jump" cannot account for the conductance difference measured, we attribute the conductance "jump" to the change in capacitance as a result of the snap-through buckling. However, we show that quantitative analysis of this phenomenon is not at all trivial, and is enabled only due to our ability to predict the exact CNT shape before and after the transition. Understanding this mechanism enables a fast characterization of fabricated devices and improves our understanding of their behavior, key in developing this technology further and better design. As an example, we show how the hysteretic trait of this phenomenon is indicative of the ability to achieve static latching, useful for RF switches, bi-stable relays, and memory devices.