Multi-spectral InAs/GaAs-based quantum dot infrared photodetector with quaternary (InAlGaAs) capping operates at low bias voltage

The quantum dot infrared photodetector is an emerging technology for advanced imaging. Multi-color imaging technologies are favored as they extend the boundary of applications of the device. We report multi-spectral performance of MBE grown InGaAs/GaAs (device A) and InAs/GaAs (device B) based photodetector with In0.21Al0.21Ga0.58As capping at 77K. Spectral response measurement of device A shows the presence of a strong photoresponse at 10.2µm. Device B exhibits a four color response (5.7, 9.0, 14.5, 17 and 20 µm) over a broad range (520µm) at very low bias voltage.