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

Abstract

In this paper, we present the results of recent development of ZnSe-based room temperature blue–green lasers grown by MBE. A novel laser structure design is proposed and realized, involving a combination of alternately-strained ZnSSe/(Zn,Cd)Se layers in a short-period superlattice waveguide with a single 2–3 monolayer thick CdSe fractional monolayer (FM) active region incorporated 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-organized dot-like islands providing effective carrier localization and serving as radiative recombination centers. As a result, significantly improved optical and electronic confinement as well as high quantum efficiency have been obtained, leading to the lowest ever reported threshold power density (4 kW/cm 2, 300 K) and increased degradation stability with respect to conventional ZnCdSe QW lasers.