ELECTRICAL AND ELECTROMECHANICAL CHARACTERISTICS OF NANOASSEMBLED CARBON NANOTUBE

ELECTRICAL AND ELECTROMECHANICAL CHARACTERISTICS OF NANOASSEMBLED CARBON NANOTUBE THIN FILM RESISTORS ON FLEXIBLE SUBSTRATES Wei Xue and Tianhong Cui Department of Mechanical Engineering, University of Minnesota, Minneapolis, USA Transducers’ 07 Speaker: Wen-Fan Liao ID: g 946220

Outline v Introduction v Experiments v Device Characteristics v Conclusion v References

Introduction This paper report the fabrication of single-walled carbon nanotube (SWNT) thin-film on plastic substrates with layer-by-layer self-assembly v assemble SWNTs on flexible substrates and explore the properties of the SWNT thin films which are built with alternating layers of SWNTs and PDDA v

Experiments Polyelectrolytes(+ ) CNTs(-) naonoparticles Ref : T Cui and W Xue, “Assembling three-dimensional carbon nanotube-based cantilever arrays, ” SPIE Newsroom 2007 Layer-by-layer self-assembly of polyelectrolytes/CNTs and polyelectrolytes/nanoparticles

Experiments (PDDA/SWNT)n (PDDA/PSS)2 Ref : W Xue and T Cui, “Deposition and characterization of layer-by-layer nano selfassembled carbon nanotube multilayer thin films” IEEE NEMS 2007 1μm v v (a) Structure of self-assembled SWNT multilayer thin film (b) SEM image of assembled SWNTs

Experiments Cr/Au Ref : W Xue and T Cui, “Deposition and characterization of layer-by-layer nano selfassembled carbon nanotube multilayer thin films” IEEE NEMS 2007 v Schematic structure of a SWNT thin-film resistor built on a flexible substrate

Experiments v v (a) Flexed transparency film with prepatterned electrodes (b) Transparency coated with 5 layers of SWNTs

Experiments v 4156 A Precision Semiconductor Parameter Analyzer v up to four probes v Measurements include I-V curve, Id-Vg graphs, etc Ref : http: //www. ee. byu. edu/cleanroom/HP 4156 A. phtml

Device Characteristics 6. 37 MΩ 0. 30 MΩ 0. 21 MΩ 0. 14 MΩ R 10 =6. 37 MΩ R 0 =1. 35 MΩ Rn =(R 0×R 10)/[R 0+(n-10) ×R 10] v Characteristics of SWNT thin-film resistors on flexible substrates

Device Characteristics G 14 = △R 14/R 14 = 38. 2% G 16 = △R 16/R 16 = 47. 1% v Resistance versus mechanical deformation of SWNT thin-film resistors

Device Characteristics v Schematic models for axial deformation of SWNT on different topographies

Conclusion demonstrated the fabrication and characterization of SWNT multilayer thin films on flexible substrates v MEMS/NEMS devices such as pressure sensors, accelerometers, and magnetic sensors have the potential to be developed and fabricated v

References v v Wei Xue and Tianhong Cui, “Electrical and electromechanical characteristics of nano-assembled carbon nanotube thin film resistors on flexible substrates, ” Transducers’ 07, Lyon, France, June 2007 Wei Xue and Tianhong Cui, “Deposition and characterization of layerby-layer nano selfassembled carbon nanotube multilayer thin films, ” IEEE NEMS 2007, Bangkok, Thailand, pp. 371 -376, January 2007 Tianhong Cui and Wei Xue, “Assembling three-dimensional carbon nanotube-based cantilever arrays, ” The International Society for Optical Engineering - SPIE Newsroom - Micro/Nano Lithography & Fabrication, http: //spie. org/x 17490. xml, DOI: 10. 1117/2. 1200710. 0901, 2007 http: //www. ee. byu. edu/cleanroom/HP 4156 A. phtml

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