▎ 摘　　要

NOVELTY - The FET has a nanoscale material layer arranged on a substrate, and defining an electrically conducting and chemically sensitive channel, where the material layer and the channel extend between and are electrically connected to drain electrode and source electrode. A polar fluid induced gate terminal is created by a polar fluid exposed to the material layer, where polar fluid comprises a target analyte, and includes a charge concentration sufficient to induce polar fluid gate voltage that optimizes the gate voltage versus channel current characteristics of the FET in response to the analyte. USE - FET i.e. nanoscale FET such as graphene based FET, for use in applications such as bio probes, and implants. ADVANTAGE - The FET utilizes a simultaneous modulation by voltages creates a tri-gated structure that can used to shift the device operation to a desired electrical performance in a more controlled fashion using minimal energy. The FET utilizes polar solution to provide polar fluid gate terminal (PFGT) on graphene FET (GFET) amplified an electrical response across the channel, thus increasing sensitivity and providing reversibility. DETAILED DESCRIPTION - The nanoscale material comprises graphene, carbon nanotubes, molybdenum disulphide, boron nitride, metal dichalcogenides, phosphorene, nanoparticles, quantum dots, fullerene, two dimensions nanoscale material, three dimensions nanoscale material, and nanoscale materials. The polar fluid comprises sweat, breath, saliva, earwax, urine, semen, blood plasma, a bio-fluid, a chemical fluid, an air sample and a gas sample. The target analyte comprises an electrolyte, glucose, lactic acid, interleukin 6, a cytokine, cortisol, cholesterol, vitamins, a protein, a drug molecule, a metabolite, peptides, an amino acid, a DNA, ribonucleic acid, an aptamer, an enzyme, a biomolecule, a chemical molecule, and a synthetic molecule. INDEPENDENT CLAIMS are also included for the following: (1) a method for sensing a target analyte in a polar fluid (2) a system for sensing a target analyte in a polar. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a base device with dielectric and gate metal. Dielectric layer (7) Gate metal (8)