Operation and speed of a Photo detector Q.1 A si photodiode has an Si layer of width 20microns. The p layer is very thin (.1 microns). The pin is reversed biased by 100V and then illuminated by with an optical pulse 900nm. What is the duartion of the photocurrent if absorption occurs over the i-si layer? (given the absorption coefficient at 900nm is 30x10/m) Drift velexity (in s-> 10% Electron 104 Hole 10 102 101 107 105 106 Electric fiell (Vm)