Platinum-gate

Spetz A., Armgath M., and Lundstrom L, Hydrogen and ammonia response of metal-silicon dioxide-silicon structures with thin platinum gates, J. Appl. Phys., 64, 1274-1283, 1988. 

Spetz, A., Armgarth, M. and Lundstrom, I. (1987), Optimization of ammonia-sensitive structures with platinum gates, Sensors and Actuators, 11,349-65. 

Only a small amount of work has been published on platinum-gate FET-based hydrogen sensors. Lundstrom and co-workers (13) showed that... 

Ross et al (22) presented results on hydrogen and ammonia sensitivity of thin platinum-gate MOSFET devices. They concluded that the mechanism of response of these devices was as previously suggested, and cited literature on the dissociation of ammonia on silicon dioxide supported platinum catalysts as additional evidence. Lundstrom et al (23) presented further results on the two-metal capacitors. They outlined three possible modes of response of these devices, the first the same as the hydrogen sensitivity on palladium-gate devices (which they immediately ruled out), the second as already described. 

Between the pulses the gate is disconnected from the potentiostat, (open-circuit phase) and the potential of the platinum gate is dictated by the redox-state of the polymer The potential is approaching its equilibrium value, while the electrons spread from the electrode to equilibrate throughout the polymer film The redox polymer attached to the platinum surface functions as a condenser... 

The hydrogen sensitivity of palladinm-oxide-semiconductor (Pd-MOS) strnctnres was first reported hy Lnndstrom et al. in 1975 [61]. A variety of devices can he nsed as field-effect chemical sensor devices (Fignre 2.6) and these are introdnced in this section. The simplest electronic devices are capacitors and Schottky diodes. SiC chemical gas sensors based on these devices have been under development for several years. Capacitor devices with a platinum catalytic layer were presented in 1992 [62], and Schottky diodes with palladium gates the same year [63]. In 1999 gas sensors based on FET devices were presented [64, 65]. There are also a few publications where p-n junctions have been tested as gas sensor devices [66, 67]. 

The transfer gates 4 and the charge transfer gates 5 may be formed as MIS structures or as Schottky barrier structures using aluminium or platinum. Furthermore, the gallium arsenide substrate may be substituted for a silicon substrate. 

Jentoft, R. E., Tsapatsis, M. A., Davis, M. E., and Gates, B. C., Platinum clusters supported in zeolite LTL Influence of catalyst morphology on performance in n-hexane reforming. J. Catal. 179,565 (1998). 

S. Ruba, B. C. Gates, P. Vijayanand, R. R. Grasselli, and H. Rnozinger, An active and selective alkane isomerization catalyst iron - and platinum - promoted tungstated zirconia, J. Chem. Soc. Chem. Commun. 321-322 (2001). 

S. Kuba, P. Lukinskas, R. Ahmad, F. C. Jentoft, R. K. Grasselli, B. C. Gates, and H. Knozinger, Reaction pathways in n - pentane conversion catalyzed by tungstated zirconia effects of platinum in the catalyst and hydrogen in the feed, J. Catal. 219, 376-388 (2003). 

The processing of the devices and the casting of the membranes is identical to the steps as described in Section A.2, except for the additional deposition of a platinum actuator electrode around the gate of the ISFET. A cross-sectional view of the membrane-covered ISFET with actuator is shown in Fig. 8. Also in this case, the membrane consists of an 8 gm thick layer of polystyrene beads with a diameter of 0.1 /tm and agarose. 

McVicker GB, Kao JL, Ziemiak JJ, Gates WE, Robbins JL, Treacy MMJ, Rice SB, Vanderspurt TH, Cross VR, Ghosh AK (1993) Effect of sulfur on the performance and on the particle size and location of platinum in Pt/KL hexane aromatization catalysts. J Catal 139 48... 

Chang J-R, Koningsberger DC, Gates BC (1992) Structurally simple supported platinum clusters prepared from [PtjjlCO) on magnesium oxide. J Am Chem Soc 114 6460... 

Fig. 12 An electronic device based on a single rolled-up sheet of carbon atoms. (From Ref. () In the figure, a CNT (red about 1 nm in diameter) bridges two closely spaced (400 nm apart) platinum electrodes (labeled source and drain) atop a silicon surface coated with an insulating silicon oxide layer. Applying an electric field to the silicon (via a gate electrode, not shown) turns on and off the fiow of current across the nanotube, by controlling the movement of charge carriers onto the nanotube. (View this art in color at www.dekker.com.)...

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