Chemical field-effect transistors

Comparable is the CHEMFET (Chemical Field Effect Transistor), a chemical sensor on a FET, e.g., for H , Na, K and Ca2+ in blood, four CHEMFETs had been mounted on one plate [Clin. Chem., 30 (1984) 1361. 

Low-cost, disposable, Si02/Si3N4 chemical field effect transistor (ChemFET) microsensors have been fabricated for pH measurements and adapted to biochemical applications by using polyvinyl alcohol (PVA) enzymatic layers deposited and patterned... 

Successful operation of potentiometric chemosensors opened up the possibility for the fabrication of chemical field-effect transistors (chemFETs) and ion-selective field-effect transistors (ISFETs). A sensing element in these devices, i.e. the MIP film loaded with the molecular, neutral or ionic, respectively, imprinted substance is used to modify surface of the transistor gate area. Apparently, any change in the potential of the film due to its interactions with the analyte alters the current flowing between the source and drain. 

Molecular Materials for the Transduction of Chemical Information into Electronic Signals by Chemical Field-Effect Transistors... 

Jackel, F. et al.. Prototypical single-molecule chemical-field-effect transistor with nanometer-sized gates, Phys. Rev. Lett. 92, 188303, 2004. 

Semiconductor electrodes ion-selective field effect transistors (ISFETs) are semiconductor devices used to measure ionic species in solution. They are sometimes called chemical field-effect transistors or ChemFETs. The transistor is coated with silicon nitride, which is in contact with the test solution via an analyte-sensing membrane and also connected to a reference electrode. A variation in the concentration of the analyte ions changes proportionally with the voltage of the ISFET. ISFETs are rugged, have a faster response time than membrane electrodes and can be stored dry. 

Xie D., Jiang Y, Pan W., Jiang J., Wu Z., and Li Y, Study on bis [phthalocyaninato] praseodymium complex/silicon hybrid chemical field-effect transistor gas sensor. Thin Solid Films, 406, 262-267, 2002. 

F. Jackel, M. D. Watson, K. MUllen and J. P. Rabe, Prototypical single-molecule chemical-field-effect transistor... 

At a higher level of miniaturisation, work has been directed at constructing miniature electrochemical cells for biosensor applications (20). Chemical field effect transistors (CHEMFETs) and ion selective field effect translators (ISFETs) have received a high level of research interest for almost a decade ( but with little tangible results in terms of commercially available systems. Some recent research has been directed at integration of the sensor and control electronics into a discrete, disposable device (21). Although further development is still required, the... 

CNT-based gas sensors have shown good electrical response as well. It was established that chemiresistors and chemical field-effect transistors are probably the most promising types of gas sensors based on CNTs (Kong et al. 2000 Bondavalli et al. 2009 Wang and Yeow 2009 Zhang and Zhang 2009 Hu, et al. 2010). Typical configuration of such sensors is shown in Fig. 1.10. It has to be pointed out that for this kind of sensor the research has essentially focused on SWCNTs, because MWCNTs are only metallic and therefore unsuitable to fabricate chemiresistors and transistors. 

In their pioneering approach, Rabe etal. developed a prototype single molecule chemical-field-effect transistor (CFET) based on self-assembly of a molecular dyad (Figure 20a) which consists of an electron rich hexa-/7m-hexabenzocoronene (HBC) core covalently linked to six electron deficient anthraquinone (AQ) subunits. Figure 20(b) displays an STM image of monolayer... 

ChemFETs (chemical field effect transistors) combined with a reference electrode. Although the transducer principle varies from the potentiometric sensors, the result is comparable. 

Fig. 41 Schematic drawing of a prototypical single-molecule chemical-field-effect transistor. (Reproduced with permission from Ref. [161])...

Miniaturised sensors have been made which are able to be placed in small spaces using semiconductor technology. The various kinds of sensors include ion-selective field-effect transistors (ISFETs) and chemical field-effect transistors (ChemFETs), as well as chemiresistors. 

A ChemFET, a chemical field-effect transistor, is a type of FET that is a chemical sensor where the charge on the gate electrode is due to a chemical process. In principle, it may be used to detect atoms, molecules and ions in liquids and gases. For example, the SiOa gate material has Si-OH groups on the surface, which can be used for covalent attachment of organic molecules and polymers. 

Sant,W., Pourciel, M.L., Launay, J., Do Conto, T., Martinez, A., and Temple-Boyer, P. (2003). Development of chemical field effect transistors for the detection of urea. Sens. Actual. B 95(l-3) 309-314. 

Dithiamacrocycle incorporating a phosphine donor group 79 was synthesized (Scheme 12.30) and tested as neutral carrier in poly(vinylchloride) membranes. C104 —selective chemical field-effect transistor and ion-selective electrode... 

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