We report the experimental work on the GaAs metal-semiconductor-metal photodetectors with recessed cathode and/or anode. The recessed-cathode detectors exhibit much superior dc and speed performance to the conventional one because of the enhancement of hole transport in this structure, Full-width at half-maximum and fall time of the temporal response were measured to be 21 and 13 ps at 5 V bias on a 50x50 mu m(2) detector with a finger width and spacing of 3 mu m.
