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Bulk BeCdSe layer lattice-matched to a GaAs substrate, as well as a BeCdSe/ZnSe quantum well (QW) structure have been grown using the submonolayer digital alloying mode of molecular beam epitaxy. The structures have demonstrated bright photoluminescence up to room temperature and good structural quality. Stimulated emission under optical pumping has been obtained for a 2 nm BeCdSe/ZnSe multiple QW structure at 80 K. The bowing parameter of the energy gap of this ternary alloy has been estimated as about 4.5 eV.

A mid-IR laser based on a hybrid pseudomorphic AlGaAsSb/InAs/CdMgSe heterostructure with a III–V/II–VI heterovalent interface at the 0.6-μm-InAs active region has been fabricated by molecular-beam epitaxy on p+-InAs substrate. It provides ∼1.5-eV asymmetric barriers for both electrons and holes in InAs, inhibiting carrier leakage from the active region. Despite a nonoptimal defect density at the CdMgSe/InAs interface (106–107 cm−2), the structure demonstrates lasing at ∼2.78 μm (up to 100 K) under pulse injection pumping with the threshold current density of 3–4 kA/cm2. The proposed design is promising for high-power mid-IR lasers operating at room temperature.

The paper presents an overview of recent activity in fabrication by molecular beam epitaxy and study of AlGaSbAs/InAs/(ZnTe)/Cd(Mg)Se hybrid pseudomorphic heterostructures with an InAs/II-VI heterovalent interface either in the active region (in case of mid-IR laser diodes) or in the InAs quantum well (QW). Different approaches to fabrication of the defect-free InAs/II-VI interface are discussed, as well as their effect on crystalline properties and an electronic band structure at the interface. The hybrid mid-IR laser diodes are characterized by a dramatically improved carrier (hole) and optical confinement in the InAs-based active region. Clear confining effects are observed in the photoluminescence from a ~7-nmthick InAs QW with CdMgSe and AlAsSb barriers. An existence of 2D electron gas in such QWs of ~16 nm in a thickness is proved by observation of Shubnikov-de Haas oscillations. The obtained results are prospective both for mid-IR optoelectronics and spintronics.