The S8664-20K from Hamamatsu Photonics is a Photodiode with Wavelength Range 320 to 1000 nm, Capacitance 11 pF, Dark Current 0.6 to 6 nA, Responsivity/Photosensitivity 0.24 A/W, Active Area Diameter 2 mm (Photosensitive). More details for S8664-20K can be seen below.