Semiconductor quantum structures for infrared detection using nano-patterned grating geometry

Abstract

We demonstrate the fabrication and the operation of nano-structured grating type infrared (IR) detectors defined on GaAs/AlGaAs heterostructures by using electron beam lithography and a chemical wet etching method. The grating structures provide effective light coupling mechanism based on the diffraction effect. As the grating widths are reduced close to the depletion of the quantum well, we observe a systematic increase of the normalized responsivity of the detectors. The light spectrum also exhibits an additional feature of a blue shift. These are possible signatures of lateral quantum confinement.