The S5821-01 from Hamamatsu Photonics is a Photodiode with Wavelength Range 320 to 1100 nm, Capacitance 3 pF, Dark Current 0.05 to 2 nA, Responsivity/Photosensitivity 0.45 to 0.6 A/W, Active Area Diameter 1.2 mm. More details for S5821-01 can be seen below.