PARTIALLY RELAXED MULTIQUANTUM-WELL INGAAS ALGAAS HETEROJUNCTION PHOTOTRANSISTOR OPERATING AT 955-970NM/

The authors report a partially relaxed InGaAs multiquantum well based heterojunction phototransistor with high responsivity in the transmiss ion window of the GaAs substrate which shows no degradation in perform ance due to lattice relaxation. The peak responsivity increased from 1 0A/W at 0.5 mu W incident optical power to 100A/W at 50 mu W, correspo nding to a current gain of 925. At 8V collector-emitter voltage the re sponsivity is constant from 957 to 973nm, with a responsivity of 5A/W at 0.5 mu W and 55A/W at 50 mu W.