A　self-driven　photosensor　with　signal-reversal　response　has　the　potential　to　work　as　a　photodetector　in　complex　environments　with　multiple　signals　owing　to　better　signal　recognition　and　enhanced　signal-processing　efficiency.　Herein,　a　metal-semiconductor-metal　photodetector　based　on　ambipolar　WSe2　with　two　electrodes　comprising　two-dimensional　(2D)　van　der　Waals　(vdWs)　metal　Fe3GeTe2　and　semimetal　graphene　was　proposed　to　form　an　asymmetrical　metal-contacted　architecture　with　different　Schottky　barrier　heights.　The　regulating　gate　field-induced　Fermi　level　shift　in　WSe2　can　be　used　to　manipulate　the　WSe2　channel＇s　carrier　type,　resulting　in　a　polarity-reversible　photodetector　without　a　bias　voltage.　Furthermore,　the　photovoltaic　effect　can　be　observed　from　wavelengths　of　450　nm　(visible)　to　850　nm　(infrared)　without　external　voltage.　The　large　open　voltage　is　-0.177　V　and　short-circuit　current　is　17　nA　under　a　650-nm　excitation　wavelength.　The　reported　WSe2-based　photodetector　exhibits　excellent　properties　under　zero　bias,　including　a　large　photo-to-dark　current　ratio　greater　than　10(6)　with　dark　current　less　than　1　fA,　photovoltaic　performance　with　an　external　quantum　efficiency　of　27.14%,　an　excellent　detectivity　of　3.4x10(10)　Jones,　and　a　high　responsivity　of　116.38　mA/W.　Rapid　electron　transfer　occurs　at　the　interface　between　WSe2　and　vdWs　electrodes,　resulting　in　a　370-mu　s　response　speed　owing　to　the　clean　and　nondestructive　interfaces　between　vdWs　metals　and　WSe2.　This　study　demonstrates　the　wide　application　prospect　of　the　vdWs　metal　Fe3GeTe2　as　an　electrode　forming　a　Schottky　junction　for　realizing　a　photodetector　without　an　external　voltage　and　accelerates　the　development　of　2D　photosensors　with　various　working　modes.