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

• We demonstrate high quantum efficiency (17%) InAs/GaAs p-type quantum dot infrared photodetector.
• The p-type hole response displays a well-preserved spectral profile, independent of the applied bias.
• The p-type quantum dot photodetector exhibits a strong far-infrared response up to 70 μμm.

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 μμm 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 μμm. An external quantum efficiency of 17% is demonstrated. The studies show the promise of p-type QDs for developing infrared photodetectors.