A calibration method for group V fluxes and impact of V/III flux ratio on the growth of InAs/InAsSb type-II superlattices by molecular beam epitaxy

A calibration method for group V fluxes is demonstrated for the growth of InAsxSb1−x alloys and strain-balanced InAs/InAsxSb1−x superlattices on GaSb substrates by molecular beam epitaxy for IR optoelectronic device applications. The structural and optical properties of these structures grown with varying V/III flux ratios are investigated using several characterization methods, including X-ray diffraction (XRD), photoluminescence (PL), and reflection high energy electron diffraction. Samples grown at 450 °C with Sb/In flux ratios from 1.0 to 2.0 and As/In flux ratios from 1.2 to 2.5 lead to Sb mole fractions ranging from 0.078 to 0.34. High structural and optical quality superlattices for Sb mole fractions up to 0.34 are verified by XRD and low-temperature PL measurements. When varying both Sb mole fraction and period, superlattice structures are demonstrated with low-temperature emission wavelengths ranging from 3.6 to 7.1 μm.

► A reproducible calibration methods of group V fluxes is demonstrated.
► High quality strain-balanced InAs/InAsSb superlattices have been grown using MBE.
► High structural quality and precise strain balance are confirmed by XRD and TEM.
► Emission wavelength range from 3.6 to 7.1 μm is achieved.