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 ${\text{2.03}}\times {\text{10}}^{-3}\;{\text{mA/cm}}^{2}$ 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  μ m at 77 K, and the corresponding detectivity was ${\text{5.78}}\times {\text{10}}^{8}\,{{\text{cm}\cdot \text{Hz}}}^{1/2}{\text{/W}}$ . 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.