Year of Publication

2011

Degree Name

Master of Science in Electrical Engineering (MSEE)

Document Type

Master's Thesis

College

Engineering

Department

Electrical Engineering

First Advisor

Dr. Vijay Singh

Abstract

A theoretical model is developed for calculating the sensitivity of resistive sensors based on aligned multiwall carbon nanotubes (MWCNT) embedded in the pores of alumina membranes. Aligned MWCNTs offer more surface area as each CNT acts as a landing site for detecting gas species. The MWCNTs behave as a p-type semiconducting layer; when the bus bar contacts are placed at either end of the top surface the resistance between the contacts responds to oxidizing (resistance decreases) and reducing gases (resistance increases). The model presented in this thesis aims to understand the device resistance dependence upon the MWCNT resistance, and the sensitivity dependence upon the device structure and design. The model was utilized for enhancing the sensitivity of MWCNT sensors for ammonia (30% sensitivity) and nitrogen dioxide (40% sensitivity) gases. Experimental results from sensitivity measurements are compared with theoretical predictions.

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