WSE2/SNSE2 Heterostucture Tunnel Field-Effect Transistor for Ph Sensing

Field-effect transistor (FET) biosensors based on two-dimensional (2D) materials have drawn significant attention due to their outstanding sensitivity. However, the Boltzmann distribution of electrons imposes a physical limit on the subthreshold swing (SS), and 2D-material biosensor with sub-60 mV/dec SS has not been realized, which hinders further increase of the sensitivity of 2D-material FET biosensors. We demonstrate the biosensor based on WSe
2
/SnSe
2
heterostructure tunnel field-effect transistor (TFET) with graphene contacts. The tunnelling effect of 2D materials in aqueous solution is observed for the first time with the minimum SS of 29 mV/dec. Its sensitivity reaches 820/pH, surpassing the sensitivity of FET biosensors based on single 2D material (WSe
2
) by approximately an order of magnitude.