Dual-color short-wavelength infrared photodetector based on InGaAsSb/GaSb heterostructure

Abstract

We report the spectral response characteristics of a dual–band infrared photodetector based on nBn photodiode configuration–with GaSb and InGaAsSb absorption layers and a ternary layer of AlGaSb that serves as unipolar barrier in between—which has independent access to both sides. The resulting structure has detection capability in the short-wavelength infrared ranges, cut-off wavelength of 1.6 μm (SWIR1; GaSb) and 2.65 μm (SWIR2; InGaAsSb) depending on the applied bias. The dual-band photodetector was evaluated by current–voltage (I–V) characteristics, spectral response, and detectivity (D*). The measured values of D* at 300 K were 2.3 × 1012 cm·Hz1/2·W−1 (at 1.5 μm) and 2.1 × 1011 cm·Hz1/2·W−1 (at 2.25 μm).