InAs/GaSb type-II superlattice structures and photodiodes grown by metalorganic chemical vapor deposition

We report on the characterization and performance of epitaxial structures and photodiodes based on InAs/GaSb type-II superlattices grown by metalorganic chemical vapor deposition. Interfacial layers were introduced at the superlattice interfaces to compensate the tensile strain and hence to improve the overall material quality of the superlattice structures. The optimal morphology and low strain was achieved via a combined interfacial layer scheme with InAsSb+InGaSb layers. Using this scheme, a p-i-n photodiode structure with a 360-period InAs/GaSb superlattice was grown on a GaSb substrate, which operates at 78 K with a cut-off wavelength of ∼8 μm and a peak responsivity of 0.6 A/W at ∼6 μm.