Resonant cavity enhanced InAs∕In0.15Ga0.85As dots-in-a-well quantum dot infrared photodetector

The authors demonstrate the design, growth, fabrication, and characterization of resonant cavity enhanced InAs∕In0.15Ga0.85As dots-in-a-well (RC-DWELL) quantum dot infrared photodetector (QDIP) and compare it with a standard DWELL detector. They measured peak photoresponse at the resonant wavelength of 9.5μm for the RC-DWELL photodetector. The peak responsivity was measured to be 0.76A∕W at 1.4V and the peak detectivity was 1.4×1010cmHz1∕2∕W at 0.5V at a temperature of 77K. The photocurrent density increased in comparison with the standard DWELL structure with the same active region by a factor of 6 at Vb=2.1V and 80K. A factor of 6 increase in responsivity and factor of 3 increase in detectivity at 1.2V and 77K were also observed in the resonant cavity enhanced DWELL sample. The quantum efficiencies for the RC-DWELL sample were calculated to be ∼10% at 9.5μm and 1.25% at 10μm for the standard DWELL sample. They conclude that the RC-DWELL is a promising improvement for QDIP-based infrared detection applications.