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

Abstract

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 InAs_0.8Sb_0.2/Al_0.2Ga_0.8Sb 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.