Ultra-low threshold ZnSe-based lasers with novel design of active region

In this paper, we present the results of recent development of ZnSe-based r oom temperature blue-green lasers grown by MBE. A novel laser structure des ign is proposed and realized, involving a combination of alternately-strain ed ZnSSe/(Zn,Cd)Se lavers in a short-period superlattice waveguide with a s ingle 2-3 monolayer thick CdSe fractional monolayer (FM) active region inco rporated into a ZnSe quantum well(QW). The CdSe FMs transform under certain MBE conditions into the dense array of 15-30 nm-size CdSe-based self-organ ized dot-like islands providing effective carrier localization and serving as radiative recombination centers. As a result, significantly improved opt ical and electronic confinement as well as high quantum efficiency have bee n obtained, leading to the lowest ever reported threshold power density (4 kW/cm(2), 300 K) and increased degradation stability with respect to conven tional ZnCdSe QW lasers. (C) 1999 Elsevier Science B.V. All rights reserved .