Effect of the Sb content and the n− and p−GaSb(100) substrates on the physical and chemical properties of InSbxAs1-x alloys for mid-infrared applications: Analysis of surface, bulk and interface

Antimonide-based family holds the potential for developing a new generation of mid-infrared applications. Here, we report on the growth of InSbxAs1-x alloys on n− and p−type GaSb(100) substrates varying the Sb mole fraction (x), using the liquid phase epitaxy (LPE) technique. We show that the ternary alloy grown on the n−type GaSb substrate presents higher crystalline quality, thermal diffusivity and interfacial thermal conductivity, as compared to the one grown on pin equation type GaSb substrates which decrease as the Sb mole fraction (x) in the layer increases. Our results demonstrate that the InSbxAs1-x/n−GaSb heterostructure reaches the thermal equilibrium faster than the InSbxAs1-x/p−GaSb structure, with lower roughness, strain, as well as a better chemical abruptness at substrate-layer interface. We also find that the growth mechanism of the InSbxAs1-x alloy is constituted by In−As and In−Sb bonds. Furthermore, the Raman scattering spectra measured at different layer depths evidence that the crystalline quality improves with depth and allow the identification of an intrinsic depletion region. Since the InSbxAs1-x alloy presents a long-range atomic order grown on both n− and p−type GaSb substrates, the phonon-plasmon coupled L− and L+ modes are observed, and from the L+ coupled mode, we obtain the intrinsic carrier concentration and its variation with the Sb mole fraction. Therefore, this work provides important guidance on the structural, thermal, and chemical properties of the surface, bulk and interface of InSbxAs1-x alloys, that should be considered to improve the performance of future devices, such as better heat dissipation.$ [Display omitted] •InSbxAs1−x alloys on n− and p−GaSb substrates were grown by LPE.•Effect of the Sb content on InSbxAs1−x properties was found.•Analysis of surface, bulk and interface of InSbxAs1−x alloys.•Study of thermal diffusivity, interfacial conductivity and growth mechanism.•Study of crystalline quality and intrinsic carrier concentration.