Influence of Sb2 soaking on strained InAs0.8Sb0.2/Al0.2Ga0.8Sb multiple quantum well interfaces.

InAsSb/AlGaSb systems have potential in mid-wavelength infrared detection and laser fields. Thus, their heteroepitaxial crystal quality and heterointerface are of great importance. Herein, the quantum well structure based on InAs0.8Sb0.2/Al0.2Ga0.8Sb was grown by interruption with and without Sb2 soaking methods by molecular beam epitaxy to optimize the interface quality and adjust the heterostructure strain. Narrow and well-defined satellite peaks in high-resolution x-ray diffraction patterns manifest good crystal quality of the sample with 15 s Sb2 soaking interruption. The relaxation of sample A without Sb2 soaking interruption is ∼23% calculated by the reciprocal space mappings, while there is no relaxation found in sample B with 15 s Sb2 soaking. High-resolution transmission electron microscopy and energy-dispersive spectroscopy were carried out. They showed sharp and coherent heterointerfaces generated by adding interruptions with an Sb2 overpressure before and after InAsSb layer growth. Furthermore, the atomic force microscopy images of a 5 × 5 μm2 scan area show that the surface of sample B with Sb2 soaking contains atomic steps with a root-mean-square roughness of 1.44 Å. The photoluminescence peaks of the samples located in the range of 3–4 µm show that these InAsSb/AlGaSb material systems have potential applications in mid-wavelength optoelectrical devices. [ABSTRACT FROM AUTHOR]