Electrochemical sensing of arsine and silane by the amperometric gas sensor using gold electrode

Amperometric detection of arsine and silane was investigated by electrochemical gas sensors. The working electrodes of sensors were constructed by a gold thin-film (AuTF), a platinum thin-film (PtTF) and a platinum black electrode (PtB) formed on gas permeable membranes. The AuTF sensor showed good response for the low concentration of arsine and silane. The selectivity for arsine by AuTF sensor against organic solvent vapors expected to be existing in a factory was superior to that using the platinum electrode sensors. The good linearities of oxidation current against arsine and silane concentrations could be obtained at the optimum electrode potential of the sensor. These results indicate the AuTF sensor can be utilized as more reliable sensor in practical field than ordinary sensors using the platinum electrode. The number of electrons with the electrochemical oxidation of arsine can be determined to be 6 by means of the two AuTF sensors.