In $$_x$$x Ga $$_{1-x}$$1 - x As $$_y$$y Sb $$_{1-y}$$1 - y epilayers with a fixed In content of $$\textit{x}$$x = 0.145 were grown on GaSb(100) substrates using liquid-phase epitaxy (LPE). The lattice mismatch between the quaternary epilayers and substrates was analyzed for different As contents ( $$\textit{y}$$y ) by X-ray $$\omega$$ω -2 $$\theta$$θ . Epilayers with As content between $$\textit{y}$$y = 0.120 and $$\textit{y}$$y = 0.124 exhibited a positive lattice mismatch, leading to compressive strain. These samples showed a high crystalline quality and flat surfaces, as confirmed by high-resolution X-ray diffraction (HR-XRD) and atomic force microscopy (AFM). Quaternary alloys with As content between $$\textit{y}$$y = 0.133 and $$\textit{y}$$y = 0.141 displayed a negative lattice mismatch, resulting in tensile strain. Structural defects in these samples were evidenced by HR-XRD and on AFM micrographs. Raman measurements also revealed that lateral strain has a direct impact on the intensities of the LO-like, phonon–plasmon and disorder-activated longitudinal acoustic modes. For all In $$_x$$x Ga $$_{1-x}$$1 - x As $$_y$$y Sb $$_{1-y}$$1 - y films, photoluminescence (PL) spectra showed a bound exciton (BE) transition, with additional features observed in samples under tensile strain, indicating the involvement of native defect centers and donor–acceptor pairs. This study provides new insights into the effect of lateral strain on the crystalline and surface quality, and optical properties of quaternary alloys, relevant for novel optoelectronic applications.

We report the growth of In0.145Ga0.855As0.132Sb0.868 layers on GaSb(100) substrates by the liquid phase epitaxy (LPE) technique using the ramp-cooling method. We achieved a near-lattice-matched epitaxial growth with a lattice mismatch of between the quaternary layer and GaSb(100) substrate due to optimal growth parameters. Aberration-corrected scanning transmission electron microscope (AC-STEM) confirmed the high crystalline quality of the quaternary layer and the low lattice mismatch in the heterostructure, without the presence of linear or planar defects. Also, the Secondary Ion Mass Spectrometry (SIMS) technique evidenced a uniform distribution of the atomic elements along the quaternary layer and an abrupt interface between the In0.145Ga0.855As0.132Sb0.868 layer and the GaSb substrate. Plasmon-phonon interactions were observed by Raman spectroscopy indicating that the crystalline quality increases at greater depth in the sample with respect to the surface. The quaternary layer presented a uniform and flat morphology, and luminescence emission attributed to the recombination of bound exciton states at 641 meV. The structural, chemical, and optical properties of the In0.145Ga0.855As0.132Sb0.868 layer demonstrated that it could be auspicious material for infrared range optoelectronic applications. Likewise, the LPE technique successfully shows that it should be used to grow near-lattice-matched heterostructures.

We propose a strain-optimized design strategy for lattice-matched InAs_1−xSb_x/Al_1−yIn_ySb Type-I quantum wells (QWs) that emit across the near-to mid-infrared spectrum (2–5 µm). By combining elastic strain energy minimization with band offset calculations, we identify Type-I alignment for Sb contents (x ≤ 0.40) and In contents (0.10 < y ≤ 1). At the same time, Type-II dominates at higher Sb compositions (x ≥ 0.50). Using the transfer matrix method under the effective mass approximation, we demonstrate precise emission tuning via QW thickness (L_W) and compositional control, achieving a wavelength coverage of 2–5 µm with <5% strain-induced energy deviation. Our results provide a roadmap for high-efficiency infrared optoelectronic devices, addressing applications in sensing and communications technologies.