In this work, characteristics of silicon-based p(+) type, intrinsic (I), n(-) type (Si-PIN) photodiodes with active area of 3.5 x 3.5 mm(2), 5.0 x 5.0 mm(2), or 7.0 x 7.0 mm(2) and their possible usage in optoelectronics were studied. The devices were fabricated in the Radiation Detector Application and Research Center (NURDAM) of Bolu Abant izzet Baysal University, Turkey. To acquire the device specifications, the current-voltage (I-V) and the capacitance-voltage (C-V) measurements were carried out in the photoconductive mode. Quantum efficiency and spectral responsivity measurements were performed in the photovoltaic mode. Both measurements were carried out in a dark environment at room temperature. The measured values of the dark current (I-dc) and the capacitance of photodiodes were -6.97 to -19.10 nA and 23 to 61 pF at -5 V, respectively. The quantum efficiency measurements of the devices increased up to 66%. P responsivity was found to be 0.436 +/- 1 mA/W at 820 nm. The results indicate that the I-dc current and the performance of the devices were improved. Therefore, the devices can be utilized for optoelectronics applications and commercial usage.