Zero-Bias Power-Detector Circuits based on MoS₂ Field-Effect Transistors on Wafer-Scale Flexible Substrates

The design, fabrication, and characterization of wafer-scale, zero-bias power detectors based on 2D MoS₂ field-effect transistors (FETs) are demonstrated. The MoS₂ FETs are fabricated using a wafer-scale process on 8 μm-thick polyimide film, which, in principle, serves as a flexible substrate. The performances of two chemical vapor deposition MoS₂ sheets, grown with different processes and showing different thicknesses, are analyzed and compared from the single device fabrication and characterization steps to the circuit level. The power-detector prototypes exploit the nonlinearity of the transistors above the cut-off frequency of the devices. The proposed detectors are designed employing a transistor model based on measurement results. The fabricated circuits operate in the Ku-band between 12 and 18 GHz, with a demonstrated voltage responsivity of 45 V W^-1 at 18 GHz in the case of monolayer MoS₂ and 104 V W^-1 at 16 GHz in the case of multilayer MoS₂ , both achieved without applied DC bias. They are the best-performing power detectors fabricated on flexible substrate reported to date. The measured dynamic range exceeds 30 dB, outperforming other semiconductor technologies like silicon complementary metal-oxide-semiconductor circuits and GaAs Schottky diodes.