Abstract
Quantum-dot (QD)/quantum-well (QW) mixed-mode infrared photodetectors are demonstrated in this letter for multicolor detection in both the midwavelength infrared (MWIR) and long-wavelength infrared (LWIR) ranges. Responses at 4.3, 5.6, and 10.3 μm are observed for the device. The polarization-dependent response of the device has shown that the higher normal-incident absorption is observed for the MWIR peaks, which suggest that the intraband transitions in the QD structure are responsible for the MWIR peaks while the intraband transition in the QW region is responsible for the LWIR peak. A model is also established to explain the transition mechanisms of the device. © 2008 American Institute of Physics.