May 10, 2011
Suspended carbon nanotube thin-film suits NEMS
Engineers in the US have fabricated 2D micropatterns and 3D suspended thin-film structures using carbon nanotubes as a building block via lithography-compatible layer-by-layer nano self-assembly. They used well established IC fabrication techniques along with the "bottom-up" construction of nanotubes and applied a further process to manufacture the suspended micro-beam, which is a basic structure for actuators in micro/nanoscale systems.
The group, led by Tianhong Cui at the University of Minnesota, US, has explored the fundamental issues of fabrication by characterizing the devices step by step. As a result, the scientists observed reduced electrical resistance of the stripe film pattern when thin-film was released. More importantly, the flexural Young's modulus they found using a nanoindentation technique was on the order of 500–800 GPa. The stiff CNT thin-film micropatterns and suspended beam architecture have a variety of potential applications including novel physical sensors, nanoelectromechanical switches and other M/NEMS devices.
The team is using the bridge-like structures for nanoswitch applications thanks to the electrically conductive nature and excellent mechanical stiffness of the material. The group has studied the lithography-compatible layer-by-layer nano self-assembly process in detail, and has previously configured nanomaterials as thin-film transistors and biosensors.
Additional information including a detailed version of the fabrication procedure is available in the journal Nanotechnology.
About the author
The study was conducted by researchers from the Technology Integration and Advanced Nano/microsystems (TIAN) Lab at the Department of Mechanical Engineering, University of Minnesota, US. Dr Dongjin Lee was a PhD student when the study was conducted. He is currently a postdoctoral associate at the Korea Advanced Institute of Science and Technology (KAIST), Korea. The research group, TIAN Lab, is led by Prof. Tianhong Cui. The research goal of the group is to investigate the fundamental electrical and mechanical principles of new materials for MEMS/NEMS and low-cost micro/nanomanufacturing approaches, utilizing nanotechnology to effectively enhance the performance of micro/nanosystems.