SENSING BEHAVIOR OF SEMICONDUCTING METAL-OXIDES FOR THE DETECTION OF ORGANOPHOSPHORUS COMPOUNDS

Sensing behaviours of doped SnO2 and ZnO elements have been investigated for the detection of organophosphorus compounds. Among the elements examined, SnO2- or ZnO-based elements doped with basic oxides such as CaO and MgO exhibit a promising sensing property to DMMP (dimethyl methylphosphonate). Reasonable sensitivity can be obtained at concentrations of DMMP down to 44 ppb. The test gas was oxidized upon exposure to the oxides. It has been suggested that the basic oxide additives are effective in aiding dissociative adsorption of DMMP on the oxide surface, thus facilitating the oxidation reaction of the test gas.