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

Low dark current InAs/GaAs quantum dot infrared photodetector (QDIP) is dem onstrated. The dark current reduced for over three orders of magnitude by i ntroducing a thin AlGaAs current blocking layer. This thin AlGaAs can reduc e 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 ab out 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.