We etched a n-Si wafer to form arrays of Si-nanotips emerging from a SiO2 layer on which we transferred CVD grown monolayer graphene. We measured the electrical characteristics of the junction and found a rectifying behavior with On/Off ratio increasing with decreasing temperature and at room temperature higher than 1.5·102 at ±0.5V. The ideality factor of the diode is near-ideal with a value of 1.5 at room temperature. The Schottky barrier height monotonically increases from reverse to forward bias, with a value of 0.36±0.02 eV at zero bias. This behavior can be explained as a combination of graphene features and image force barrier lowering. The diode shows photoresponse and fotovoltaic effect when exposed to visible light. The photoresponse is pronounced at near infrared (IR) radiation.