Mid-infrared emission from In(Ga)Sb layers on InAs(Sb).

We demonstrate infrared light emission from thin epitaxially-grown In(Ga)Sb layers in InAs(Sb) matrices across a wide range (3-8 µm) of the mid-infrared spectral range. Our structures are characterized by x-ray diffraction, photoelectron spectroscopy, atomic force microscopy and transmission electron microscopy. Emission is characterized by temperature- and power-dependent infrared step-scan photoluminescence spectroscopy. The epitaxial In(Ga)Sb layers are observed to form either quantum wells, quantum dots, or disordered quantum wells, depending on the insertion layer and substrate material composition. The observed optical properties of the monolayer-scale insertions are correlated to their structural properties, as determined by transmission electron and atomic force microscopy.