Mechanistic investigation on an all solid state fluorine sensor

A semiconductor field effect structure Si/SiO2/Si3N4/LaF3/Pt can be used fo r the detection of fluorine in air. Depending on the preparation, two diffe rent sensor types were investigated having advantages at low or high fluori ne concentrations, respectively. Combining these sensors concentrations bet ween 0.01 and 1000 ppm can be detected. The mechanism of the sensor was sho wn to be an electrochemical charge transfer at the three-phase boundary LaF 3/Pt/gas. Differences in the mechanism of the two sensor types are due to p artial fluorination of the platinum at concentrations higher than 10 ppm. ( C) 2000 Elsevier Science Ltd. All rights reserved.