Holly Tourtillott University of Missouri

1. Characterization of Carbon Nanofibers/Cavities and Microelectrode Fabrication for Biosensors Application Holly Tourtillott University of Missouri • Faculty Advisor: Dr. Uche Wejinya Graduate Student Advisor: Zhuxin Dong Department of Mechanical Engineering, University of Arkansas July 20, 2009 Micro and Nano Systems Engineering Laboratory, University of Arkansas

2. Outline • Carbon Nanotubes • Microelectrode Fabrication • Characterization of Carbon Nanofibers on Electrodes • Experiment and Results • Conclusion and Future Work • References Micro and Nano Systems Engineering Laboratory, University of Arkansas

3. Carbon Nanotubes • Carbon nanotubes have remarkable electrical, mechanical and thermal properties. • This research focuses on carbon nanotubes band structure to ultimately identify their electrical properties. • Using the Atomic Force Microscope and dielectrophoresis, the band structure and therefore conductivity of the CNTs can be determined. • The DEP process is used to align and determine the characteristics of the nanofibers. Micro and Nano Systems Engineering Laboratory, University of Arkansas

4. Microelectrode Fabrication • The DEP process requires the fabrication of a microelectrode chip. Micro and Nano Systems Engineering Laboratory, University of Arkansas

5. Microelectrode Fabrication • The DEP process requires the fabrication of a microelectrode chip. Micro and Nano Systems Engineering Laboratory, University of Arkansas

6. Characterization of Carbon Nanofibers on Microelectrodes • Using an Agilent 5500-ILM Atomic Force Microscope (AFM), scanning of a microelectrode chip may be conducted. • The AFM is a very high-resolution type of scanning probe microscope that has resolution of fractions of a nanometer. We can use this microscope to measure the z-direction of a nanoparticle and in our case the height of the microelectrode chip fibers. Micro and Nano Systems Engineering Laboratory, University of Arkansas

7. Characterization of Carbon Nanofibers on Microelectrodes Micro and Nano Systems Engineering Laboratory, University of Arkansas

8. Characterization of Carbon Nanofibers on Microelectrodes C1 C2 C3 C4 C5 C6 C7 C8 C9 C1 C9 A3 A5 A7 A2 A4 A8 A1 A6 A9 200 μm square A1 = Array 1 C1 = Contact Pad 1 Micro and Nano Systems Engineering Laboratory, University of Arkansas

9. Characterization of Carbon Nanofibers on Microelectrodes Cavity Fiber 9 arrays under camera view to scan A 9×9µm area scanned in one array, cavities and fibers are found. 3D topography image Micro and Nano Systems Engineering Laboratory, University of Arkansas

10. Experiment and Results Micro and Nano Systems Engineering Laboratory, University of Arkansas

11. Conclusion and Future Work • Throughout this research, the fabrication of a microelectrode chip was completed as well as the scanning of two NASA microelectrode chips. • Future work includes the use of the completed microelectrode chip that was fabricated in this research. This chip was made specifically for the DEP process of aligning carbon nanotubes and ultimately further research in assisting the biosensor applications technology. Micro and Nano Systems Engineering Laboratory, University of Arkansas

12. References • -Microscope: Agilent 5500 ILM, Atomic Force Microscope • -Website: http://en.wikipedia.org/wiki/Carbon_nanotubes • -Book: Carbon Nanotube- Multifunctional Material, Edited by Prakash R. Somani and M. Umeno, Applied Science Innovations • -Website: http://ieeeexplore.org/nanotubes • Publication: Zhuxin Dong, Uchechukwu C. Wejinya, Haibo Yu, and Imad H. Elhajj. “Design, Fabrication and Testing of CNT Based ISFET for NANO pH Sensor Application: A Preliminary Study.” • Publication: KunalGhosh. “Electronic Band Structure of Carbon Nanotubes.” Micro and Nano Systems Engineering Laboratory, University of Arkansas

13. Thank You! Any Questions? Micro and Nano Systems Engineering Laboratory, University of Arkansas