shout-out to "varicap" diodes, which are also monstrously fucked-up: someone looked at the parasitic junction capacitance of a cheap silicon diode, and then decided that looked like a neat mechanism for electronically tunable filters. Worked well enough that someone started selling intentionally large and capacitative diodes for the purpose. Don't worry, though -- even if you don't have one of these funky components, you can mimic it with an appropriately biased 2N2222!
If a photodiode works, why not turn up the reverse bias to the point of getting a single-photon Geiger-mode avalanche photodiode? There is no limit to the bullshit you can do to a diode!
