Structural and optical optimization of ZnSe‐based laser heterostructures with graded index waveguide

Abstract

We report on structural and photoluminescence (PL) studies of wide gap II‐VI laser heterostructures involving the graded index waveguide (GIW) based on short period Zn(Mg)SSe/ZnSe superlattices (SLs) and the active region comprising single or multiple electronically‐coupled CdSe/ZnSe QD sheets. Precise compensation of elastic stresses in the SL waveguide and optimization of the ZnSe/GaAs initial growth stage have resulted in good crystalline quality of the laser structures and reduction of the extended defect density down to 104 cm‐2. Express monitoring of the defect density by using the photoluminescence microscope was supported by transmission electron microscopy studies. PL data have demonstrated efficient transport of nonequilibrium carriers through the GIW SLs to the active region (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

MBE growth, structural and transport properties of alternately-strained ZnSSe/CdSe superlattices with effective band-gap 2.5–2.6 eV

“…The single CdSe/ZnSe QD layers has been introduced into the structures to study the vertical carrier transport in SLs as well as for the express estimation of the extended defects density in as-grown structures using a PL microscopy technique [9]. To minimize the density of stacking faults (SFs) at the III-V/II-VI heterointerface the low-temperature ($ 210 1C) migration enhanced epitaxy (MEE) growth mode has been applied at the initial growth stage of a ZnSe buffer layer.…”

“…To minimize the density of stacking faults (SFs) at the III-V/II-VI heterointerface the low-temperature ($ 210 1C) migration enhanced epitaxy (MEE) growth mode has been applied at the initial growth stage of a ZnSe buffer layer. This procedure allows reducing the SFs density below 10 5 cm À 2 [9,10]. The growth rates of Zn(S,Se) were controlled insitu by recording RHEED specular spot intensity oscillations after the II-VI growth initiation immediately before the SLs growth.…”

Optically pumped quantum-dot Cd(Zn)Se/ZnSe laser and microchip converter for yellow—green spectral region

“…Optimisation of the initial stage of the ZnSe/GaAs heterointerface formation according to the procedure described in [5] allowed us to achieve better structural perfection of laser heterostructures and to decrease the stacking fault density down to 10 5 cm -2 , which is evidenced by the structure surface microphotograph obtained using a fluorescent microscope (Fig. 1).…”

“…Previously, we showed the possibility of creating low-threshold highly efficient optically pumped lasers based on Cd(Zn)Se/ZnMgSSe heterostructures with the active region consisting of one or several planes of self-assembled Cd(Zn)Se/ZnSe quantum dots (QDs) in a graded-index waveguide [4,5], as well as the possibility of creating A 2 B 6 /A 3 N converters based on these lasers for the green ( l = 520 - 550 nm) spectral region [6,7]. The possibility of industrial production of active elements for this converter, as well as a noticeable decrease in the cost of commercial InGaN LDs used in Blu-ray discs ( l ~ 405 nm) and DPL projectors ( l ~ 445 nm), determine the prospects for the creation of this device.…”

CdSe/ZnCdSe Quantum Dot Heterostructures for Yellow Spectral Range Grown on GaAs Substrates by Molecular Beam Epitaxy

“…4, with the maximum achieved QD luminescence wavelengths being as long as 600 nm and 586 nm, respectively. However its RT peak intensity is still rather weak 400 times lower than that at the GIW laser heterostructure of optimal design [6]. The PL spectra at T = 77 and 300 K of the GIW laser heterostructure are presented in Fig.…”