The G12181-020K from Hamamatsu Photonics is a Photodiode with Wavelength Range 0.9 to 1.9 µm, Capacitance 1000 to 2000 pF, Dark Current 50 to 500 nA, Responsivity/Photosensitivity 0.9 to 1.1 A/W, Active Area Diameter 2 mm. More details for G12181-020K can be seen below.