Date of Award

12-2009

Degree Name

Master of Science in Engineering

Department

Electrical and Computer Engineering

First Advisor

Dr. Alyce Dickinson

Second Advisor

Dr. Scott T. Gaynor

Third Advisor

Dr. John Austin

Fourth Advisor

Dr. Eric Fox

Access Setting

Masters Thesis-Campus Only

Abstract

A Silicon Nitride (Si3N4) based fingerprint sensor comprising of a 256 x 300 array of integrated capacitive devices and a 5 MHz gold plated quartz crystal microbalance sensor were used for a qualitative study of the dielectric property of various chemical as well as biological species. Analysis on 5 ul solutions of sucrose, acetyl salicylic acid and glycine used as adsorbents on a 10 x 10 pixel sensor area produced digitized output values between 0 and 255 which was then converted to analog voltage via a read out circuit. The change in the frequency and impedance outputs observed at the microbalance revealed a qualitative calibration curve for the liquids based on their dielectric property. The investigation on the capacitive and acoustic wave transducers demonstrated an increase in the output voltage, frequency and impedance with a decrease in the relative dielectric constant of sample solutions tested. The outputs were also used to understand the selective detection of each sample solution, through a range of concentrations, and determine the saturation limit of the sensors.

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