2-COLOR INFRARED DETECTION USING INTERSUBBAND TRANSITIONS IN MULTIPLESTEP QUANTUM-WELLS WITH SUPERLATTICE BARRIERS

A dual-band multiple quantum well infrared photodetector has been fabr icated for the near and mid-infrared detection. The structure consists of InGaAs/GaAs step quantum wells separated by AlGaAs/GaAs superlatti ce barriers. The step quantum wells are designed to have two bound sta tes and a quasi-continuum above the superlattice barriers. The bound-t o-bound and bound-to-continuum transitions are employed for the dual-b and detection. The superlattice barriers are used to extract the photo current from the bound-to-bound transition with a relatively low exter nal electric field, which keeps the dark current low. This work demons trates the use of a new quantum well structure for the fabrication of multicolor quantum well infrared photodetectors. (C) 1997 American Ins titute of Physics.