Hybrid MES-MOSFET with dual-band dynamically tunable photoresponse for optoelectronic encryption

Metal semiconductor field-effect transistors (MESFETs) offer an efficient platform for low-power optoelectronic encryption systems. However, their practicality is limited by inadequate channel carrier modulation and severe Fermi level pinning at the interface. Here, we introduce an asymmetric dual-gate architecture, the MES-MOSFET, which integrates a van der Waals Schottky top gate 1T-VSe2 with a conventional SiO2/Si back gate to control the 2H-WS2 channel. This design leverages the inherent advantages of MESFETs while overcoming typical limitations of precise doping control using a metal-oxide-semiconductor (MOS) bottom gate. The device achieves a low subthreshold swing of 71.0 mV/dec while simultaneously demonstrating tunable mobility through highly efficient dual-gate control. Furthermore, the MES-MOSFET exhibits remarkable and gate-tunable photoresponse across distinct spectral regions. Under 520 nm illumination, the responsivity is dynamically tunable across six orders of magnitude. Moreover, at 1550 nm, the device demonstrates a unique switching behavior between positive and negative photoresponse, controlled by the bottom gate voltage. The superior optoelectronic dual-gate modulation and the dual-band dynamically tunable photoresponse enable the MES-MOSFET platform to function as a secure information processing system, opening new possibilities for next-generation encryption technology.