Quantum-Dot Infrared Photodetectors

InAs quantum dot infrared photodetectors based on bound-to-bound intraband transitions in undoped InAs quantum dots are reported. A1GaAs blocking layers were employed to achieve low dark current. The photoresponse peaked at 6.2 tm. At 77 K and —0.7 V bias the responsivity was 14 mA/W and the detectivtiy, D*, was 1010 cmHz112/W. By introducing InGaAs cap layers, a QDJP with bias-controllable two-color characteristic was demonstrated.