1：Experimental Design and Method Selection:

The study involves the fabrication and characterization of graphene–WS2–Si heterostructure photodetectors. The methodology includes photolithography, etching, sulfurization of WO3 film, transfer of graphene, and deposition of electrodes to realize the van der Waals heterostructure.

2：Sample Selection and Data Sources:

An n-type Si wafer with 285 nm thermally oxidized SiO2 was used as the substrate.

3：List of Experimental Equipment and Materials:

AFM (FM-Nanoview1000), SEM (VEGA3 SBH, TESCAN), Raman spectrometer (Andor, SR-5001-A-R), Agilent B2902A, supercontinuum source white light laser (SC-PRO, YSL Photonics), acousto-optic monochromator (AOTF-PRO, YSL Photonics), power meter (1935-C, Newport), mechanical chopper (SR540, Stanford Research Systems), oscilloscope (TDS 3054B, Tektronix), low-noise current amplifier (SR570, Stanford Research Systems), lock-in amplifier (SR830, Stanford Research Systems).

4：Experimental Procedures and Operational Workflow:

The fabrication process includes defining the contact region with WS2, depositing WO3 film, sulfurizing it into WS2, depositing Ag electrode, and transferring single layer graphene on the WS2 film. Electrical properties and photoresponse were measured in a probe station.

5：Data Analysis Methods:

The photocurrent and photoresponsivity were analyzed as functions of light intensity and wavelength. The response time was determined from time-resolved current measurements under modulated light irradiation.