P7 - Ammonium and Potassium Ion-Sensitive Field-Effect Transistors
- Event
- iCCC2026 - iCampus Cottbus Conference
2026-05-05 - 2026-05-07
Cottbus - Band
- Poster
- Chapter
- Bio- & Umweltsensorik
- Author(s)
- L. T. Kühne, C. Beale, M. Wambold, E. Kurth, O. R. Hild - Fraunhofer IPMS, Dresden, C. Ruffert - Fraunhofer IPMS, Cottbus
- Pages
- 147 - 150
- DOI
- 10.5162/iCCC2026/P7
- ISBN
- 978-3-910600-10-2
- Price
- free
Abstract
The integration of potassium-selective membranes on ion-sensitive field-effect transistors (ISFETs) was successfully reproduced in this study, confirming results previously reported [1]. A sensitivity of 60.2 mV/Dec was achieved in KH₂PO₄/NaH₂PO₄ buffer solution at pH 7, which is in close agreement with the value of 59.3 mV/Dec reported in earlier work. This outcome demonstrates the capacity for stable and reproducible membrane integration, with the potential to approach the theoretical Nernstian response. Furthermore, the coefficient of determination R₂ for all sensors was consistently above 99.75 %, indicating excellent linearity and reliability of the sensor signal. However, measurements performed in a KCl solution buffered with tris(hydroxymethyl)aminomethane to pH 7.6 revealed a significantly reduced sensitivity of 49.36 mV/Dec, despite similar experimental conditions and a still high R₂-value above 99.5 %. This discrepancy suggests a noticeable influence of interfering sodium ions on the sensor’s performance, particularly regarding the selectivity + sensor reveals a lower sensitivity. The sensitivity is of the potassium-sensitive membrane. A comparison of the NH₄ 25.11 mV/Dec and exhibits both a slightly increased variance and a reduced coefficient of determination.