We report on the experimental work on GaAs MSM photodetectors with recessed cathodes and/or anodes. The recessed-electrode structure results in effective collection of the deep holes due to the uniformly distributed and strengthened electric field as well as shortened transit path. As compared to the conventional device, improved de responsivity from 0.14 to 0.24 A/W and temporal response including full-width at half-maximum from 27 to 22 ps, fall time from 117 to 68 ps, and peak amplitude from 116 to 212 mV were simultaneously observed at 5 V bias in the recessed-electrode device with an active area of 50 x 50 mu m(2) and a finger width/spacing of 3 mu m, respectively.
