Evaluation of Doped Phthalocyanines and a Chemically-Sensitive Field Effect Transistor for Detecting Nitrogen Dioxide
Abstract
This study involved the design and fabrication of an integrated circuit microsensor for the detection of nitrogen dioxide; metal-doped phthalocyanine compounds were evaluated as a candidate chemically-sensitive membrane, and their performance was compared with respect to sensitivity, reversibility, and specificity. The microsensor consisted of the integration of an array of nine sensing elements with amplifiers, a reference amplifier, and an analog multiplexer. The nine individual sensing elements used an interdigitated gate electrode field-effect transistor (IGEFET) coupled to a serially-connected pair of inverting amplifiers using metal-oxide-semiconductor field-effect transistors(MOSFETs). The interdigitated gate electrodes were coated with thin films of cobalt (II) phthalocyanine (CoPc), copper phthalocyanine (CuPc), lead phthalocyanine (PbPc), nickel (II) phthalocyanine (NiPc), and (undoped) phthalocyanine (Pc). An excitation signal was applied to the integrated circuit, and the multiplexed electrical response was measured in the time-domain and the frequency-domain. The electrical response was evaluated upon exposure to 20-, 80-, and 320-ppb of nitrogen dioxide (NO2) and diisopropyl methylphosphonate (DIMP) using filtered room air (less than 5% relative humidity) as the diluent. The electrical response was evaluated for film thickness of approximately 1500 A and 500 A. The rank ordering of the sensitivity of the materials to nitrogen dioxide from the most to least sensitive was: CoPc, NiPc, CuPc, PbPc, and then (undoped) Pc. Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 04, 1989
- Accession Number
- ADA215662
Entities
People
- Thomas J. Jenkins
Organizations
- Air Force Institute of Technology