InAs/GaAs quantum dot and dots-in-well infrared photodetectors based on p-type valence-band intersublevel transitions

InAs/GaAs quantum dot (QD) and dots-in-well (DWELL) infrared photodetector (QDIP) based on p-type valence-band intersublevel hole transitions are reported. Two response bands observed at 1.5-3 and 3-10 mu m are due to optical transitions from the heavy-hole to spin-orbit split-off QD level and from the heavy-hole to heavy-hole level, respectively. The p-type hole response displays a well-preserved spectral profile (independent of the applied bias) observed in both QD and DWELL detectors. At elevated temperatures between 100 and 130 K, the DWELL detector exhibits a strong far-infrared responses up to 70 mu m. An external quantum efficiency of 17% is demonstrated. The studies show the promise of p-type QDs for developing infrared photodetectors. (C) 2014 Elsevier B.V. All rights reserved.