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, Hg_1–xCd_xTe. By incorporating both bismuth and arsenic in the appropriate proportions, we demonstrated InAs_0.004Sb_0.983Bi_0.013 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 InAs_ySb_1–x–yBi_x 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 InAs_0.004Sb_0.983Bi_0.013 have accessed the longest wavelengths of any lattice-matched, bulk III–V alloy to date. Altogether, these results demonstrate the strong potential of InAs_ySb_1–x–yBi_x for high-performance optoelectronic devices operating across the long-wave infrared.