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Polymer film-coated high electron mobility transistors, based on GaN heterostructures, as sensors for some benzene derivatives

Krzysztof R. Noworyta 1Paweł Prystawko 2Mike Leszczynski 2Tadeusz Suski 2Wlodzimierz Kutner 1

1. Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 52/56, Warszawa 01-224, Poland
2. Polish Academy of Sciences, Institute of High Pressure Physics (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland


Chemically sensitive field-effect transistors (ChemFETs) have been extensively investigated and widely applied as sensors for various chemical and biological analytes [1] since their invention by Bregveld in 1970 [2]. Main advantages of ChemFETs over conventional ion-selective electrodes (ISE) consist in small dimensions, fast response and possibility of integration in the sensor array or microfluidic and/or electronic systems (a lab-on-chip concept). Moreover, ChemFETs are relatively easy for mass production. Typically, SiO2/Si heterostructures are used for constructing ChemFET sensors, although organic ChemFETs are extensively investigated as well [1c]. Recently, there is a growing interest in ChemFETs based on wide-bandgap semiconductors, such as diamond, SiC and GaN. The GaN-based ChemFET sensors combine advantages of superior electrical parameters with high thermal and chemical stability. Because a GaN crystal features similar surface chemistry properties as those of metal oxides, its surface can readily be modified resulting in formation of films selectively recognizing analytes of interest. Moreover, the GaN-based ChemFET is transparent to visible light. Therefore, processes occurring on the transistor surface can simultaneously be monitored spectroscopically. Pristine and chemically modified FETs as well as high electron mobility transistors (HEMTs) based on the GaN or the AlGaN heterostructures have already been applied as sensors for determination of pH [3], anions [4] and proteins [5], as well as various gases and vapours [6]. Herein, an overview of operating principles, fabrication procedures and applications of ChemFETs for sensing purposes will be given. Development of cyclodextrin polymer coated high electron mobility transistor, based on AlGaN/GaN/sapphire heterostructure, will be presented and application of the polymer coated heterostructures for detection of benzene derivatives will be discussed. It will be shown that a-cyclodextrin polymer film modified HEMT structure can selectively detect p-nitrophenol, especially in its anionic (p-nitrophenolate) form. Moreover, attempts to develop a sensor, based on heterostructures coated by molecularly imprinted polymers of functionalised cyclodextrins, for sensing of compounds of biological importance will be described.


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Presentation: Short communication at SMCBS'2007 International Workshop, by Krzysztof R. Noworyta
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-08-31 18:51
Revised:   2009-06-07 00:44