PbS QDs/Al2O3/In0.53Ga0.47As infrared photodetector with fast response and high sensitivity

Due to the size effect, multi-exciton effect, confinement effect, and tunable bandgap, quantum dots (QDs) have gradually been used in near-infrared photodetectors. In this paper, PbS QDs were integrated with In0.53Ga0.47As materials, and a PbS QDs/In0.53Ga0.47As hybrid photodetector with Al2O3 was investigated. Passivation of PbS QDs by ligand replacement and insertion of Al2O3 reduced the dark current density from 9.24 × 10−6 to 4.67 × 10−6 A·cm−2, which enabled the detector to obtain a high responsivity of 0.97 A·W−1 under −1 V bias, and the detectivity reached 2.21 × 1010 Jones. In addition, we found that the PbS QDs/In0.53Ga0.47As near-infrared photodetector with Al2O3 obtained a fast rise and fall time, which could respond to high-frequency signals. The findings will have application in the PbS QDs/In0.53Ga0.47As hybrid near-infrared photodetectors.