Semiconductor sensors for fluorine detection - optimization for low and high concentrations

For the detection of fluorine, two different preparation methods for semico nductor gas sensors were developed, the first for concentrations between 10 and 1000 ppm (type I) and another for concentrations between 0.01 and 10 p pm (type TI). The sensitivity of type I sensors is about 116 mV/lg(p(F-2)). It is possible to detect gas concentrations down to 0.1 ppm using this sen sor. The main disadvantage is that the sensor response kinetics depends str ongly on concentration. The sensors response is fast for measurement of hig h concentrations (between 10 and 1000 ppm) but the response time is not acc eptable for the detection of small concentrations. Type II sensors show a s ensitivity of 28 mV/lg(p(F-2)) for gas concentrations between 0.006 and 10 ppm. This sensor is very fast in the detection of small concentrations of g as. (C) 2000 Elsevier Science S.A. All rights reserved.