IMPEDANCE SPECTROSCOPY ON SI-BASED CHEMICAL SENSORS WITH LANGMUIR-BLODGETT-FILMS

The use of modern impedance spectroscopy (IS) is demonstrated by measurements on chemical sensors with electrolyte/membrane + insulator/silicon structures using Langmuir - Blodgett membranes (ELBOS system). The build-up of the electrical potentials directly at the electrolyte/membrane and insulator/silicon interfaces is deduced from the measurements. For this purpose the ELBOS system is systematically divided into different parts which together can describe the sensor system. The comparison of a pH-sensitive membrane with an almost pH-insensitive membrane gives a better understanding of the distribution of the potentials.