Tracer and surface spectroscopy studies of sensitivity mechanism of mercury ion chalcogenide glass sensors

Abstract Sensitivity mechanism of mercury ion microsensors based on AgBr–Ag 2 S–As 2 S 3 thin films has been investigated using 110 Ag tracer exchange experiments, X-ray photoelectron spectroscopy (XPS) and secondary neutral mass spectroscopy (SNMS). It was found that non-linear sensor response in Hg(NO 3 ) 2 solutions is caused by at least two principal potential-generating processes: (i) Hg 2+ to Ag + ion exchange, and (ii) chemical reactions at the membrane surface involving silver and mercury species.