Dynamic modeling of rotational motion of carbon nanotubes for intelligent manufacturing of CNT-based devices
ABSTRACT Carbon nanotubes (CNTs) are good candidates for many electronics and sensing applications. These applications will require moving (deposit) and orienting carbon nanotubes to specific location, and separating CNTs with semiconducting and metallic band structure. In this paper, a new mathematical model describing precisely the rotational motion of carbon nanotubes in viscous medium (acetone) is presented. This new mathematical model correctly assumes that carbon nanotubes form a line shape after undergoing AC electric field compare to existing model that assumes carbon nanotubes to be a spherical particle. The new mathematical model is based on a newly developed model for applied torque due to electrorotation. It is also a method for controlled assembly of the CNTs on microstructures that have the plausibility to be scaled to wafer- level manufacturing. Simulation results are presented for the developed models. The developed model can be used to detect the position of carbon nanotubes and further implemented in the separation of semiconducting and metallic band structure carbon nanotubes.
Conference Proceeding: Microfluidic end effector for manufacturing of nano devices[show abstract] [hide abstract]
ABSTRACT: In this paper, a new pneumatic end effector system for micro/nano fluidic handling, nanomanufacturing, and micro/nano manipulation is presented. The new micro pneumatic end-effector system consists of a DC micro-diaphragm pump and compressor, one region of flexible latex tube, a Polyvinylidene Fluoride (PVDF) sensor for in-situ measurement of micro force, and a micro steel tip. The micro steel tip of the new pneumatic end effector system has an internal diameter (ID) of 20 mum used for handling nano entities such as carbon nanotubes, DNA, micro/nano particles as well as for microfluidic handling and droplet control. The DC micro-diaphragm pump is automatically controlled via a voltage driver interfaced with a computer in order to effectively and efficiently control suction force and pressure during microfluidic handling and droplet control in nano manufacturing. The new pneumatic end effector system with force sensing can significantly improve the success rate for handling/depositing micro/nano entities in the case of carbon nanotubes. The experimental results show the success rate of placing carbon nanotubes between electrodes can reach close to 80%. Ultimately, the technology will provide a critical and major step towards the development of automated manufacturing process for batch assembly of micro devices, manufacturing of nano devices, microfluidic droplet control, and drug deliveryRobotics and Automation, 2006. ICRA 2006. Proceedings 2006 IEEE International Conference on; 06/2006
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ABSTRACT: Properties and potential applications of carbon nanotubes are summarized by emphasizing the aspects of nanoelectronics and nanoelectromechanical systems (NEMS). The main technologies for the assembly of nanodevices through nanomanipulations with scanning probe microscopes and nanorobotic manipulators are overviewed, focusing on that of nanotubes. Key techniques for nanoassembly include the preparation of nano building blocks and property characterization of them, the positioning of the building blocks with nanometer-scale resolution, and the connection of them. Nanorobotic manipulations, which are characterized by multiple degrees of freedom (DOFs) with both position and orientation control, independently actuated multiprobes, and a real-time observation system, are one of the most promising technologies for assembling complex nanodevices in three-dimensional space. With a nano laboratory, a prototype nanomanufacturing system based on a 16-DOF nanorobotic manipulation system, the assembly of nanodevices with multiwalled carbon nanotubes are presented. Nanotube-based building blocks are prepared by directly picking up, in situ property characterization, destructive fabrication, and shape modifications. Kinds of nanotube junctions, the fundamental elements for both nanoelectronics and NEMS, are constructed by positioning the building blocks together under the real-time observation with a field-emission scanning electron microscope, connecting them with naturally existing van der Waals forces, electron-beam-induced deposition, or mechanochemical bonding.Proceedings of the IEEE 12/2003; · 6.91 Impact Factor
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ABSTRACT: We fabricated field-effect transistors based on individual single- and multi-wall carbon nanotubes and analyzed their performance. Transport through the nanotubes is dominated by holes and, at room temperature, it appears to be diffusive rather than ballistic. By varying the gate voltage, we successfully modulated the conductance of a single-wall device by more than 5 orders of magnitude. Multi-wall nanotubes show typically no gate effect, but structural deformations—in our case a collapsed tube—can make them operate as field-effect transistors.Applied Physics Letters 01/1998; · 3.79 Impact Factor