Demonstration of InAs/InGaAs/GaAs Quantum Dots-in-a-Well Mid-Wave Infrared Photodetectors Grown on Silicon Substrate

In this paper, we have demonstrated the first InAs/InGaAs/GaAs quantum dots-in-a-well (DWELL) photodetector monolithically grown on silicon substrate. We studied both the optical and electrical characteristics of the DWELL photodetectors. Time-resolved photoluminescence spectra measured from the DWELL photodetector revealed a long carrier lifetime of 1.52 ns. A low dark current density of 2.03 × 10
^-3
mA/cm
²
was achieved under 1 V bias at 77 K. The device showed a peak responsivity of 10.9 mA/W under 2 V bias at the wavelength of 6.4 μm at 77 K, and the corresponding detectivity was 5.78 × 10
⁸
cm·Hz
^1/2
/W. These results demonstrated that these silicon-based DWELL photodetectors are very promising for future mid-infrared applications, which can enjoy the potential benefit from mid-infrared silicon photonics technology.