Molecular Beam Epitaxy of InAsSbBi Lattice-Matched to InSb toward Long-Wave Infrared Sensing

InSb-based dilute-bismide alloys present a unique opportunity to span the entirety of the long-wave infrared with a bulk, lattice-matched III–V alloy that boasts greatly reduced toxicity compared to the current state-of-the-art, Hg1–xCdxTe. By incorporating both bismuth and arsenic in the appropriate proportions, we demonstrated InAs0.004Sb0.983Bi0.013 lattice-matched to commercially available InSb substrates. A kinetically limited growth regime that combined low substrate temperatures, V/III flux ratios near unity, and a relatively fast growth rate, mitigated phase separation and resulted in films with excellent structural and optical quality. In particular, the bismuth incorporation was estimated to be approximately 95% substitutional and photoluminescence from the alloy was observed at elevated temperatures up to 400 K exhibiting significant wavelength extension beyond that of InSb, out to 7.6 μm at room temperature. Furthermore, the first antimony-rich InAsySb1–x–yBix photodetector was fabricated and showed a longer cutoff wavelength than that of an InSb control detector due to the bandgap reduction caused by bismuth and arsenic incorporation. This highlights that emission and detection from InAs0.004Sb0.983Bi0.013 have accessed the longest wavelengths of any lattice-matched, bulk III–V alloy to date. Altogether, these results demonstrate the strong potential of InAsySb1–x–yBix for high-performance optoelectronic devices operating across the long-wave infrared.