Field Effect Devices Sensitive to CO at Room Temperature

Abstract

[5,10,15-Tris(2,6-dichlorophenyl)corrolate]cobalt(III) was used to chemisorb CO selectively, on the gap-gate of MOS capacitors and the state of charge monitored by voltage shifts of the photocurrent induced by pulsed illumination under constant D.C. bias, proportionally to CO concentration in air. Negative chemically induced charges at room temperature induce positive responses above and negative shifts below the threshold voltage, conforming to acceptor behavior, and the dynamic range (125 ppm) is limited by the silicon doping concentration. The linear proportionality between CO concentration and surface charge (6.46 [ppm.m2.µC-1]) corresponds to the low concentration limit of the Langmuir isotherm. Sluggish CO desorption can be compensated by photo stimulation at 395 nm.