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Proceedings Paper

Silicon integrated microsensor incorporating a metal-doped phthalocyanine organic semiconductor used to selectively detect nitrogen dioxide and an organophosphorus compound
Author(s): Edward S. Kolesar Jr.; John M. Wiseman
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Paper Abstract

A novel gas-sensitive microsensor, whose design is based upon the interdigitated-gate-electrode field-effect transistor was realized by integrating it with ia selectively-deposited, chemically-active, electron-beam evaporated copper phthalocyanine (CuPc) thin film. When isothermally operated at 150 degrees C, the microsensor can selectively and reversibly detect parts-per-billion (ppb) concentration levels of two environmentally-sensitive pollutants, nitrogen dioxide (NO2) and diisopropyl methylphosphonate (DIMP). Although the CuPc thin film chemically and electrically interacts with NO2 and DIMP, just as it will likely interact with other electrically- active gases, or combinations thereof, the selectivity feature of the microsensor was established by operating it with a 5-V peak amplitude, 2-microsecond(s) duration, 1000 Hz repetition frequency pulse, and then analyzing its time- and frequency-domain responses. As a direct consequence of this analysis, the envelopes associated with the normalized- difference Fourier transform magnitude frequency spectra reveal features which unambiguously distinguish the NO2 and DIMP challenge gas responses. Furthermore, the area beneath each response envelope may correspondingly be interpreted as a metric for the microsensor's sensitivity to a specific challenge gas concentration. Scanning electron microscopy was used to characterize the CuPc thin film's morphology. Additionally, infrared spectroscopy was employed to verify the (alpha) - and (beta) -phases of the sublimed CuPc thin films and to study the NO2- and DIMP-CuPc interactions.

Paper Details

Date Published: 17 September 1996
PDF: 11 pages
Proc. SPIE 2882, Micromachined Devices and Components II, (17 September 1996); doi: 10.1117/12.250724
Show Author Affiliations
Edward S. Kolesar Jr., Texas Christian Univ. (United States)
John M. Wiseman, Texas Christian Univ. (United States)

Published in SPIE Proceedings Vol. 2882:
Micromachined Devices and Components II
Kevin H. Chau; Ray M. Roop, Editor(s)

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