Characterizing the Sensitivity, Selectivity, and Reversibility of the Metal-DopedPhthalocyanine Thin-Films Used with the Interdigitated Gate Electrode Field-Effect Transistor (IGEFET) to Detect Organophosphorous Compounds and Nitrogen Dioxide

摘要

This study investigated the sensitivity, reversibility, and selectivity of thethin film coatings used on the interdigitated gate electrode field effect transistor (IGEFET) gas microsensor. These responses were quantified based on the dc resistance changes and frequency domain responses of the microsensor. The thin-film materials included: copper phthalocyanine (CuPc), nickel phthalocyanine (NiPc), and cobalt phthalocyanine (CoPc). The challenge gases included: diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), nitrogen dioxide, ammonia, and boron trifluoride. Tests of the CuPc thin-films and nitrogen dioxide challenges established the primary set of test parameters expected to maximize the selectivity, sensitivity, and reversibility of the thin-film coatings. A series of experiments performed at 150 C tested the other thin-film materials, on the IGEFET sensors, when challenged by listed gases. At 150 C, the nitrogen dioxide and ammonia interacted with all three film types, the boron trifluoride interacted weakly, the DIMP and DMMP show no response.