SOLUTION-GATED ION-SENSITIVE FIELD EFFECT TRANSISTOR WITH POLYMER SELECTIVE MEMBRANE FOR NITRATE DETECTION

In the paper, we fabricated a solution-gated ion-sensitive field effect transistor (IS-FET) and synthesized a selective membrane for the selective detection of nitrate. For sensor response, the level of Dirac point is measured to check the amount of nitrate in the water. Nitrate selective membrane is coated on graphene using a spin-coating method. The IS-FET is tested with four different ion solutions including chloride, sulfate, phosphate and nitrate at four different concentrations (0.1, 1, 10, 100 ppm). The Dirac point shift from-0.56 V to 0.36 V as increasing the concentration. The detection limit is 0.1 ppm, and the response time is less than 1 min.