For the effect of 5 MeV protons irradiations, the photocurrent increased with dose due to the introduction of damage from non-ionizing energy loss by the protons. The total calculated vacancy concentration increased from 5x1015-5x1017 cm-3 over the dose range investigated. The dark current increased in proportion with the implant dose, leading to a decrease in the ratio of photocurrent to dark current. The photocurrent induced by 254 nm illumination increased with dose, from ~0.3 x10-7 A at 25 ºC for a dose of 1013 cm-2 to ~10-6 A at a dose of 1015 cm-2 at a fixed light intensity of 760 µW/cm2. The photo-to-dark current ratio decreased from ~60 in the control samples to ~9 after proton doses of 1015 cm-2, with corresponding external quantum efficiencies of ~103 % in control samples, ~2 x103 % for a dose of 1013 cm-2 and 104 % for a dose of 1015 cm-2. The mechanism for the increase in photocurrent is introduction of gap states, since the dark current of the photodetectors was increased by illuminating with sub-bandgap (red or green laser light) for the proton irradiated samples.