A good photodiode should have fast response, large surface are, small capacitance
and of course low cost. I’ve been looking for a good photodiode here in Philippines and BPW34 is the best thing around. It is available in two versions, a visible light version which is packaged into a water clear casing (BPW34) and an infrared version which has a visible light cutoff filter (BPW34F). It features a 7.5 square millimeter sensitive area, responsivity of 0.62 A/W @ 850nm. The really nice thing is that it costs only about 80 pesos. Photodiodes with large surface area as this one are commonly found in lightwave communications receivers (FSO) and photoelectric smoke detectors.