Mid-infrared LEDs using InAs/sub 0.71/Sb/sub 0.29//InAs/Al/sub 0.25/In/sub 0.75/As/InAs strained-layer superlattice active layers

The use of strained-layer superlattice is a well-established technique to lower Auger recombination in the active layer of mid-IR LEDs and laser. We have shown by temperature-dependent photoluminescence experiments the Auger recombination can be further reduced by incorporating InAs spacer layer inside symmetrically-strained InAsSb/InAlAs superlattices and that the thickness of the spacer is critical for the improved operation. The layer were grown by molecular beam epitaxy on [001] InAs substrates. The crystalline quality of the grown superlattices is demonstrated by means of transmission electron microscopy, atomic force microscopy and X-ray diffraction measurement.