Ion-Sensitive Organic Field-Effect

Ion Sensitive Organic Field-Effect Transistors (ISOFETs)... 

Fig. 6.2. Cross section of an ion sensitive organic field-effect transistor (ISOFET) [14], Copyright 2001 IEEE...

Fig. 6.4. Structure of the ion-sensitive organic field-effect device proposed in [9]. Reprinted with permission. Copyright 2005, American Institute of Physics...

Fig. 6.6. Structure of an ion-sensitive organic field-effect floating gate device for chemical sensing [7]. Copyright 2006 IEEE...

Our choice for an Ion Sensitive Field Effect Transistor (ISFET) as a transducing element was based on the fact that the SiO surface contains reactive SiOH groups for the covalent attachment of organic molecules and polymers. In addition the FET has fast response times and can be made very small with existing planar IC technology. FIGURE 1... 

Niwa D, Homma T, Osaka T (2004) Fabrication of organic monolayer modified ion-sensitive field effect transistors with high chemical durability. Jpn J Appl Phys 43 L105-L107... 

Zayats, M. Lahav, M. Kharitonov, A.B. Willner, I. Imprinting of specific molecular recognition sites in inorganic and organic thin layer membranes associated with ion-sensitive field-effect transistors. Tetrahedron 2002, 58, 815-824. 

The science of chemical sensors is being studied at Manchester University for the use and application of conducting polymers [4]. Derivatives of polyaniline, polythiophene, polypyrrole and poly(phenylene vinylene) doped with various ions have been investigated as chemical sensors for biosensors, volatile organic compounds, polymer field-effect gas-sensitive transistors and optical sensors based on electrochromic properties. 

An externally applied electric field is a vectorial perturbation for chemical or orientational distributions involving interacting molecules or molecular organizations. Unlike the isotropic temperature and pressure effects on chemical-conformational transformations, direct sensitivity to electric field forces is bound to certain electrical properties of the chemical structures involved. Major structural-chemical changes in electric fields require the presence of ions, or ionized groups, or permanent or induced dipolar charge configurations, preferably in macromolecular structures. 

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