In this thesis, we focus on the optoelectronic properties of p-type graphene and ntype Silicon (Gr/Si) Schottky barrier photodiode according to the number of layers in the ultraviolet region (UV). The I-V measurements were conducted at an applied bias voltage between -0.5 and 0.5 V for each Gr/Si heterojunction. The I-V measurements taken under dark conditions showed that all Gr/Si samples with 2-, 4- and 6-layers graphene electrodes exhibited rectifying Schottky junction character, but all device's reverse saturation currents (I0) were different. Schottky barrier heights (ΦB) of the samples with 2-, 4- and 6-layers graphene electrodes were determined using the I0 values obtained from I-V measurements. Compared to the ΦB value of the sample with 2 layers graphene electrode, the ΦB of the sample with 4 layers of graphene electrode increased to ~0.82 eV, and then ΦB was found to decrease to ~0.79 eV for the 6-layer graphene electrode. Additionally, photo-response measurements were carried out at zero bias voltage and in the wavelength range of 250 – 400 nm to determine the spectral response (R) of the devices in the UV region. Compared to the device with 2 layers graphene electrode, R of the sample with 4 layers graphene electrode increased by 3 times. The result obtained revealed that using 4-layer graphene as a light-transparent electrode, Gr/Si Schottky barrier photodiode is the most applicable option for sensitive detection of light in the UV region