a graphene/n-type silicon heterojunction has been demonstrated to exhibit strong rectifying behavior and high photoresponsivity. graphene is coupled with silicon quantum dots (si qds) on top of bulk si to form a hybrid photodetector. si qds cause an increase of the built-in potential of the graphene/si schottky junction while reducing the optical reflection of the photodetector. both the electrical and optical contributions of si qds enable a superior performance of the photodetector.