Ion-sensitive field-effect transistors with ultrathin Langmuir-Blodgett membranes

Autor: Michael J. Schöning, F. Kauffmann, B. Hoffmann, A. Steffen, Hans Lüth, Peter Kordos, R. Erbach, M. Sauke, Michel Marso
Rok vydání: 1995
Předmět:
Zdroj: Sensors and Actuators B: Chemical. 27:325-328
ISSN: 0925-4005
DOI: 10.1016/0925-4005(94)01611-k
Popis: Novel ISFET devices coated with ultrathin Langmuir-Blodgett (LB) membranes are suitable for sodium detection in liquids. Successful deposition of a Na + -ion sensitive LB film onto structured ISFET surfaces has been achieved. The LB material consists of a rod-like LB polymer mixed with a commercially available sodium ionophore. A thin additional LB covering layer increases the sensor stability in contact with the electrolytes. The ISFET sensors show a nearly Nernstian sodium sensitivity of more than 52 mV/pNa in the range 10 -3 to 1 mol/l over a period of at least 30 days. A maximum response time after concentration changes of less than 1 min was determined. Selectivities were investigated to interfering ions like K + , Ca 2+ , Mg 2+ and H + . The obtained results are in good agreement with the sensor properties of capacitive silicon/SiO 2 structures coated with LB membranes of the same kind.
Databáze: OpenAIRE