Fig. 2: Sensor structure and performance characteristics.

a Schematic illustration of the device architecture of PPMS employing three terminals: Drain (D), Source (S), and Control Gate (CG), where V_cg modulates the channel conductivity. b Schematic demonstration of memory mode and perception mode of PPMS. Red/blue spheres denote electrons (e⁻)/ holes (h⁺). Under illumination, positive/negative gate bias induces downward/upward band bending of MoS₂, enabling carrier tunneling (indicated by black arrows) between the charge trapping layer (Se) and channel (MoS₂) for memory mode. In the absence of gate bias, rapid electron-hole recombination dominates under optical excitation without carrier tunneling, defining the perception mode. c Optical image of Se nanosheets with AFM (Atomic Force Microscopy) measured thicknesses (40.2 nm and 39.6 nm) marked by orange lines (scale bar: 10 μm). d PL(Photoluminescence) spectra and (e) Raman spectra of Se/h-BN/MoS₂ heterostructure, where Raman peaks centered at ~237 and 140 cm⁻¹ are attributed to the typical E₁/A₁ and E₂ modes of t-Se³⁷, peaks located at 383 and 408 cm⁻¹ correspond to the in-plane (E_2g) and out-of-plane (A_1g) vibration mode of MoS₂⁶⁰, and the isolated peak at 1365 cm⁻¹ is from the high-energy phonon (E_2g) of h-BN (Hexagonal Boron Nitride)⁶¹. f False-color SEM (Scanning Electron Microscopy) image (scale bar: 10 μm) g Cross-sectional TEM (Transmission Electron Microscopy) image (scale bar: 5 nm) and corresponding (h) Elemental EDS (Energy Dispersive Spectroscopy) mapping of the Se/h-BN/MoS₂ heterostructure (scale bar: 20 nm).