GaSbBi Quantum Wells for Mid-Infrared Lasers

Mid-infrared lasers are widely used in civilian and military applications. Interband cascade lasers and quantum cascade lasers are the most popular mid-infrared semiconductor lasers, which is difficult for growth, with low efficiency. GaSbBi is formed by introducing a small number of Bi atoms into GaSb, which reduces the matrix bandgap of about 39 meV/Bi%. GaSbBi quantum well (QW) lasers have already been fabricated, lasing at 2.7 μm. GaSb1–xBix/AlyGa1–yAs0.08ySb1–0.08y QWs on GaSb substrate is proposed to fabricated mid-infrared lasers. The band structures of GaSbBi/AlGaAsSb QWs with different Bi contents, Al contents and well thicknesses are calculated. Light emission from 1.4 to 6.2 μm can be achieved from GaSbBi QWs with well thicknesses of 5–20 nm, Bi contents of 0.01–0.15 and Al contents of 0–1.0. A 5 µm laser was designed with a 15 nm GaSbBi0.141/Al0.5Ga0.5As0.04Sb0.96 QW acting as the active region and the device performance was further calculated. The optical confinement factor is about 5.45% and the threshold current density is 393 A/cm2.