High performance InAs/GaAs quantum dot infrared photodetectors with AlGaAs current blocking layer

Low dark current InAs/GaAs quantum dot infrared photodetector (QDIP) is demonstrated. The dark current reduced for over three orders of magnitude by introducing a thin AlGaAs current blocking layer. This thin AlGaAs can reduce the dark current much more than the response signal. The responsivity at 0.5 V is 0.08 A/W with peak at 6.5 mum and the corresponding detectivity about 2.5 x 10(9) cm Hz(1/2/W1/2). It is the highest detectivity reported for QDIP at 77 K. (C) 2001 Published by Elsevier Science B.V.