CRYOGENIC PERFORMANCE OF A HIGH-SPEED GAINAS INP P-I-N PHOTODIODE/

The cryogenic performance of a high-speed GaInAs/InP p-i-n photodiode, with graded bandgap layers at the heterostructure interfaces, was inv estigated for the first time, DC measurements show that the dark curre nt of the diode decreases sharply as the temperature decreases from 30 0 to 200 K. A factor of 1000 in dark current reduction was found for t his photodiode, when it was cooled from room temperature to about 150 K. Similar modulation bandwidths were found for this device for temper atures between 9 and 300 K, with a bandwidth greater than 20 GHz, No d egradation was found in performance at cryogenic temperature compared to room temperature, This enables direct integration of high-speed pho todiodes with superconductive and other cryogenic electronics.