Very long wavelength quantum dot infrared photodetector using a modified dots-in-a-well structure with AlGaAs insertion layers

We report a modified dots-in-a-well (DWELL) infrared photodetector by inserting some very thin GaAs or AlGaAs layers into the InAs dots. The photoluminescence (PL) measurements indicate that the modified DWELL structure with the insertion layers (ILs) of GaAs has a larger peak intensity and a narrower PL linewidth than that without the ILs. For the modified DWELL detector with AlGaAs ILs, the peak detection wavelength reaches very long infrared window of 14.1 μm. The peak detectivity D∗ is 1.1×108 cm Hz1/2/W at 77 K under normal incidence infrared irradiation.