Fabrication of a rotary carbon nanotube bearing test apparatus

E H Cook,M S Weinberg,D J D Carter,Z S Spakovszky

doi:10.1088/1742-6596/660/1/012081

Abstract

Carbon Nanotubes (CNTs) are attractive elements for bearings in Micro-Electro-Mechanical Systems (MEMS), because their structure comprises nested shells with no bonding and sub-nanometre spacing between them, enabling relative motion with low friction and wear. A reliable bearing technology is critical to bringing rotating MEMS machines from laboratory demonstrations to common use. We report here the design and fabrication of a test rotor, a testing apparatus and testing attempts, and integration of CNTs with MEMS. The device improves on existing CNT bearing demonstrators by establishing a vertical bearing orientation (enabling superior rotor balance and speed, and drive mechanism placement flexibility) and a manufacturable process (employing CNTs grown in place by chemical vapour deposition (CVD)). The main outstanding challenge to demonstrating rotation is available CVD CNT quality.

Highlights

Carbon nanotube (CNT) based bearings are a promising approach, as Carbon Nanotubes (CNTs) have long been known to exhibit low sliding resistance between adjacent walls [7] and several experimental demonstrations have been accomplished [8,9,10,11,12,13]
Any rotating mechanical device would be a candidate for miniaturization with Carbon Nanotubes (CNTs) bearings
While it is possible to achieve release with a timed etch, in practice it was determined that better results can be obtained by securing the polysilicon rotor layer directly to the CNT, by removing the SiO2 around the upper portion of the CNT

Summary

Introduction

Carbon nanotube (CNT) based bearings are a promising approach, as CNTs have long been known to exhibit low sliding resistance between adjacent walls [7] and several experimental demonstrations have been accomplished [8,9,10,11,12,13]. Any rotating mechanical device would be a candidate for miniaturization with CNT bearings. The CNT bearing could make such flywheels feasible by enabling high-speed rotation, and by providing a low-friction support that reduces unwanted energy dissipation.

Results

Conclusion