Identifier

etd-11082007-103811

Degree

Master of Science in Electrical Engineering (MSEE)

Department

Electrical and Computer Engineering

Document Type

Thesis

Abstract

With the discovery of carbon nanotubes (CNTs), many applications have been implemented based on their unique electronic, mechanical, chemical and optoelectronic properties. One area of applications is in gas sensors for detecting, oxygen, flammable and toxic gases. In our work, the focus is on the fabrication of carbon nanotube (CNT) cantilever sensors for integration with CMOS readout chip which offer increased sensitivity. The higher surface-to-bulk ratio enhances the property and performance of the gas sensor by nanocantilevers. In this work, we present the detection method based on the change in capacitance of the single walled carbon nanotube (SWCNT) cantilever. Carbon nanotubes are capable of interacting with the gaseous species either directly or indirectly by using a polymer analyte coated on its surface. The capacitance variation technique of measuring cantilever deflection was used to measure the bending rate. The capacitance between the cantilever and the fixed electrode varies as a function of the magnitude of the bending of the cantilever which is in turn proportional to the concentration of the gas species in the surrounding environment. To measure the variation in the capacitance value, the CNT cantilever beam is considered as one of the electrodes of the capacitor and the metal film as the other. The air between the plates acts as the dielectric material. Simulations including both ANSYS for nanocantilevers and SPICE for CMOS readout chip and experimental results are presented in this research. Integration and packaging issues are also discussed in our research.

Date

2007

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Ashok Srivastava

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