II-VI/III-V structures with a heterovalent interface in the active region: New opportunities in band engineering

The paper presents an overview of recent activity in fabrication by molecular beam epitaxy and study of AlGaSbAs/lnAs/(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 similar to16 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. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.