Figure 4. The general form of electrolyte and back gated structures of FETs, which have been used for the sensing elements in Chem/BioFET: This nanomaterial-based structure has been widely used for cell, DNA, enzymatic reaction and chemical sensing; A - sensor structure; B - the most frequent nanomaterials used as sensing element and main conductive channel [103] (CC BY-SA 4.0). C - Schematic of a biosensor based on MXene FETs (adapted from [104]).