Fabrication and characterization of an InAs(Sb)/In${}_x$Ga${}_{1-x}$As${}_y$Sb${}_{1-y}$ type-II superlattice

Infrared optoelectronic devices based on type-II superlattice structures of III–V semiconductor materials have progressed significantly during the past decades. Exploring and further expanding the material space is of great significance for the development of infrared applications. Herein, a superlattice structure based on InAs(Sb)/In${}_x$Ga${}_{1-x}$As${}_y$Sb${}_{1-y}$ grown using a fractional monolayer alloy process to control the superlattice composition and structure is presented. High-order satellite peaks with a narrow full width at half maximum (31 arcs) in the X-ray diffraction patterns indicate the good crystal quality of the superlattices. Transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS) analysis validate the fractional monolayer alloy growth method. Photoluminescence measurements and k·p model calculations reveal the superior optical properties of the superlattice (sevenfold higher intensity than that of InAs/GaSb). In addition, the flexible control over the superlattice structure afforded by the method allows miniband engineering to cover the mid-wavelength and long-wavelength infrared regions. This work highlights the great potential of InAs(Sb)/In${}_x$Ga${}_{1-x}$As${}_y$Sb${}_{1-y}$ superlattices in infrared optoelectronic devices. (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)