Nearly lattice-matched Zn1-zCdzSe/Zn1-xCdxSe/Zn1-yMgySe (z > x) quantum wells for yellow emission

Abstract

The authors present the results of the modeling and epitaxial growth of a nearly lattice matched Zn1-zCdzSe/Zn1-xCdxSe/Zn1-yMgySe quantum well (QW) heterostructure with yellow emission. The ZnCdSe QW is composed of regions with two different Cd content: in the center, seven monolayers of Zn1-zCdzSe with z Cd content are surrounded on each side by eight Zn1-xCdxSe monolayers with x Cd content (z > x). These last regions are lattice matched to the Zn1-yMgySe barrier. The quantum well design and modeling was based on calculations employing the transfer matrix method. The ZnCdSe quantum well layers were grown in a layer-by-layer mode by submonolayer pulsed beam epitaxy within ZnMgSe barriers grown by molecular beam epitaxy. The low temperature photoluminescence spectrum presented yellow excitonic emission at 2.176 eV, which is in very good agreement with the model calculations. At room temperature, the emission shifted to 2.112 eV, a deep yellow color.

Second harmonic generation in asymmetric MgSe/CdSe/ZnCdMgSe quantum well structures

“…except for the bandgap values which are from Ref. . Several chosen parameters for the binary compounds and the nonzero bowing parameters for the ternary alloys are shown in Table .…”

“…In recent years, the group II–VI selenide quantum well structures have been investigated for several applications such as quantum cascade structures , short wavelength quantum well infrared photodetector , yellow laser diodes , and yellow emitters . Among the others, MgSe/CdSe/ZnCdMgSe quantum well structures have been suggested as an alternative to existing systems for applications in the optical communication wavelength 1.55m .…”

Room‐Temperature Yellow Emission of a High Cd Content (x = 0.70), Highly Strained, Layer‐by‐Layer Grown Zn1−xCdxSe/ZnSe Quantum Well

“…We start with the calculation of the energy levels of n monolayers ( n ‐MLs) thick Zn 1− x Cd x Se QWs surrounded by thick ZnSe barriers as a function of the composition to identify the structures that will present yellow emission. The energy levels of the pseudomorphic, fully strained Zn 1− x Cd x Se/ZnSe QW were calculated employing the effective mass and envelope function approximations by means of the transfer matrix method (TMM) with the parameters presented in the study by Villa‐Martínez et al [ 13 ] The excitonic transitions were calculated after the determination of the exciton binding energy following the model of fractional‐dimensional space approximation. [ 15 ] Figure 1 shows the calculated values of the excitonic transition at RT for QWs with thicknesses in the 1–10 MLs range.…”

“…[10][11][12] More recently, with the purpose of reducing QW strain effects, we have grown nearly lattice-matched Zn 1Àz Cd z Se/Zn 1Àx Cd x Se/Zn 1Ày Mg y Se (x < z) stepped QWs on ZnSe/GaAs(001). This QW heterostructure presented room temperature (RT) yellow-orange emission at 587 nm (2.112 eV) and a nice yellow emission at 570 nm (2.176 eV) at 14 K. [13] In this work, we take advantage of the sequential layer-by-layer growth mode offered by the submonolayer pulsed beam epitaxy (SPBE) technique, which allows the precise control of QW thickness and the composition of each individual atomic layer, [14] to grow a Zn 1Àx Cd x Se/ZnSe QW on GaAs (001) substrate with a quite high Cd content (x > 0.6) and good structural quality. The microscopic and optical characterization indicates excellent QW thickness uniformity, relatively low composition fluctuations, and intense excitonic emission.…”

“…[ 10–12 ] More recently, with the purpose of reducing QW strain effects, we have grown nearly lattice‐matched Zn 1− z Cd z Se/Zn 1− x Cd x Se/Zn 1− y Mg y Se ( x < z ) stepped QWs on ZnSe/GaAs(001). This QW heterostructure presented room temperature (RT) yellow‐orange emission at 587 nm (2.112 eV) and a nice yellow emission at 570 nm (2.176 eV) at 14 K. [ 13 ]…”