Non-volatile and multistate terahertz response in semi-floating-gate graphene field-effect transistors.

Two-dimensional (2D) material photodetector based on semi-floating gate (SFG) structure is expected to achieve multiple functions of information sensing, storage, and processing in a single device. Here, we demonstrated a terahertz (THz) detector based on the graphene/h-BN/graphene SFG structure. The device exhibits an excellent memory behavior and a gate-controlled non-volatile and multistate photothermoelectric (PTE) THz response. A theoretical model is established to systematically investigate the memory and PTE response characteristics, and the numerical results are well consistent with the experimental results. Our research provides valuable insights into the complex optoelectronic behavior of 2D material Semi-Floating-Gate Graphene Field-Effect Transistors (SFG-FETs) and paves the way for the realization of multifunctional photodetectors based on SFG-FET structures.