The authors report a two-color quantum well infrared photodetector at room temperature operating in the mid-and long-wavelength infrared detection. To this purpose, the band alignment is tailored and electronic properties are investigated for the proposed structure based on Ga 1−x In x As y Sb 1−y /GaSb and Al x Ga 1−x As y Sb 1−y /GaSb. As accurate knowledge of band offsets is required in device modeling, we have proceeded to theoretical investigations of the band offsets for pseudo-morphically strained and lattice-matched Ga 1−x In x As y Sb 1−y /GaSb and Al x Ga 1−x As y Sb 1−y /GaSb heterointerfaces in the whole range of alloy compositions 0 x, y 1. The carrier effective masses are deduced from the laws extracted from the k.p strain Hamiltonian laws. For the modeled heterostructure, the dark current of about 10 −1 A cm −2 at ambient temperature shows the high performance of this multi-color infrared photodetector around 5 and 12.5 μm wavelengths.

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