Deep blue emitting ZnS/ZnSe multiple quantum well lasers grown by MOVPE on (001) GaAs (original) (raw)
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Japanese Journal of Applied Physics, 1983
The successful results on surface gettering of background impurities and defects in 1.6 mm thick (111) GaAs wafers have been obtained. For the gettering, the wafers were coated by a 1000 Å thick yttrium film either on one side or on both sides followed by a heat treatment. It has allowed the electron concentration to decrease from (1-2)×10 15 cm -3 down to 10 8 -10 10 cm -3 and the mobility to increase from 1500-2000 cm 2 V -1 s -1 up to 7000 cm 2 V -1 s -1 at 300 K. The distribution profiles of the electron concentration and of the hole effective lifetime throughout the wafer thickness as well as photoluminescence spectra at 2 K have been presented.
Study of ZnCdSe/ZnSe quantum-wells grown by molecular-beam epitaxy on ZnSe substrates
Journal of Crystal Growth, 1998
ZnCdSe/ZnSe multiple quantum-well (MQW) structures were grown by MBE on ZnSe(0 0 1) substrates prepared by seeded chemical-vapour transport (SCVT) in hydrogen. Scanning force microscopy (SFM) analysis of these structures was performed. A method for the preparation of the substrate surface was found that resulted in a decrease of the root-mean-square (RMS) roughness of the MQW structure surfaces, down to 1 nm. For these structures intense cathodoluminescence (CL) from the QWs was observed. By e-beam pumping a microcavity, pulse lasing was achieved at room temperature (RT). 0 1998 Elsevier Science B.V. All rights reserved.
Optical properties of MOVPE-grown ZnS epilayers on (100) GaAs
Physical Review B, 1997
Excitonic properties of high-quality ZnS layers grown by low-pressure metal-organic vapor-phase epitaxy have been investigated using photoluminescence and absorption spectroscopy. Comparison with theoretical models has provided accurate information on eigenstates, broadening, strain, and temperature dependence of heavy-hole, light-hole, and split-off-band exciton transitions. Finally, radiative recombination due to inelastic exciton-polariton scattering is shown under strong injection rates.
Journal of Applied Physics, 2006
Several approaches have been employed to grow high-quality ZnSe epilayers on Ge/ Ge 0.95 Si 0.05 /Ge 0.9 Si 0.1 / Si virtual substrates. The ZnSe epilayers were characterized by photoluminescence spectroscopy. Migration enhanced epitaxy and inserting an in situ thermal annealing ZnSe buffer layer effectively reduced the intensity of deep level emissions from the ZnSe epilayer grown on a 6°-tilted Ge/ Ge 0.95 Si 0.05 /Ge 0.9 Si 0.1 / Si virtual substrate. Optimized conditions for growing high-quality ZnSe were used to deposit ZnCdSe/ ZnSe multiple quantum wells on Ge/ Ge 0.95 Si 0.05 /Ge 0.9 Si 0.1 / Si virtual substrates. Photoluminescence spectroscopy revealed quantum-confinement effect in the ZnCdSe multiple quantum wells. The evolution of the exciton emission peak energy and the linewidth as a function of temperature indicate a low density of localized sites in the sample with a well width of 1 nm. In the high-temperature regime, the thermal quenching of the excitonic emission intensity from ZnCdSe quantum well structures was governed by the thermal activation of carriers from quantum-well-confined states into barrier states.
Journal of Applied Physics, 1998
ZnSe films with thickness between 800 and 7500 Å were grown on GaAs͑100͒ by molecular beam epitaxy ͑MBE͒, and characterized by photoluminescence ͑PL͒, photoreflectance ͑PR͒, transmission electron microscopy ͑TEM͒, and high resolution x-ray diffraction. A first set of films was prepared with ZnSe directly grown on the GaAs substrate. Another set was prepared using an arsenic capped GaAs buffer layer grown on the GaAs substrate in a separated MBE system. PL studies at 18 K showed that the ZnSe films have more defects for samples grown directly on the GaAs substrate. The behavior of stacking faults and dislocations as a function of film thickness were investigated by TEM, and by the variation of the intensity of PL signals related to these defects. For both sets of samples the intensity of these signals decreased with increasing film thickness, but the decrease is steeper for films grown on GaAs buffer layers. A signal in PL spectra at ϳ2.7 eV was observed only for the samples grown directly on GaAs substrates, it was associated with donor-acceptor transitions involving Ga Zn and V Zn . The room temperature PR spectra showed, besides the GaAs and ZnSe band-gap signals, oscillations associated with the Franz-Keldysh effect due to internal electric fields. The strength of these fields was obtained by employing the asymptotic Franz-Keldysh model. A signal 22 meV below the GaAs band-gap energy was observed only in the PR spectra of the samples grown directly on GaAs substrates. This signal was associated with Zn interdiffused into the GaAs, and is correlated to the PL signal observed at 2.7 eV for the same set of samples.
Growth and Characterization of ZnCdMgSe/ZnCdSe Quantum Wells on InP substrates for Visible Emitters
1999
High-quality lattice-matched quantum well (QW) structures of ZnCdSe/ZnCdMgSe were grown on InP substrates by molecular beam epitaxy. Emission energies from 2.306 to 2.960 eV were measured by low-temperature photoluminescence for samples with QW thicknesses between 5 and 80 Å. Bandgap measurements indicate that these structures could be used in entirely lattice-matched blue, green, and yellow diode laser structures. Experimental measurements indicated that these structures have very little strain; hence, these materials could possibly be less prone to degradation than the Abstract current II-VI blue-green lasers grown on GaAs substrates.
Journal of Electronic Materials, 2018
We present our results related to the growth, photoluminescence characterization and modelling of a quantum well (QW) involving a type II heterostructure, Zn 1-x Cd x Se/ZnTe/Zn 1-x Cd x Se, confined within ZnSe barriers with a type I band alignment. We show that this type of hybrid QWs may be employed for the elaboration of Zn 1-x Cd x Se/ZnSe/GaAs based red emitters without exceeding a Cd content around 42%. The design of the ZnSe/ Zn 1Àx Cd x Se/ZnTe/Zn 1Àx Cd x Se/ZnSe QW was based on calculations employing the transfer matrix method under the effective mass, envelope function approximation. The QW was epitaxially grown at 275°C on a semi-insulating GaAs (001) substrate by a combination of molecular beam epitaxy for the ZnSe barriers, submonolayer pulsed beam epitaxy for the ZnCdSe layers of the QW and atomic layer epitaxy for the central ZnTe QW layer. A heterostructure with a central region of 2 ZnTe monolayers surrounded at each side by seven monolayers of Zn 1Àx Cd x Se, with x $ 0.41, presented a room temperature exitonic deep red emission with a peak at 1.829 eV.
Effect of structural imperfections on luminescence of ZnCdSe/ZnSe quantum wells
Journal of Alloys and Compounds, 2004
The structural and luminescence properties of Zn 1−x Cd x Se/ZnSe multi-quantum well (MQW) structures with high molar fraction of cadmium (30-50%) and wide ZnSe barriers (50, 100 and 500 nm) grown by molecular beam epitaxy (MBE) have been investigated by high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) methods. It is shown that the fluctuations of composition within the quantum well layer determine the full-width at half maximum (FWHM) of the QW photoluminescence peak. The unusual polarization characteristics of this photoluminescence have been observed. The emission peak in the edge geometry is strongly polarized perpendicularly to the QW plane. This effect is ascribed to the localization of the ground-state heavy-hole-like excitons in the regions with increased cadmium content.
Microstructural study of quantum well degradation in ZnSe-based laser diodes
physica status solidi (c), 2004
The possibility to grow CdZnSSe quantum structures with a high structural quality is extremely important for light emitting devices in the blue-green spectral range. However, during device operation the degradation of the quantum well reduces the lifetime severely due to the formation of dark spot and dark line defects, which are not clearly understood. To investigate the mechanisms of defects formation degradation studies were performed for ZnSe-based laser diodes with quaternary CdZnSSe quantum well structures by means of electroluminescence, high-resolution X-ray diffraction and transmission electron microscopy. It was found that the degradation is closely connected to a blue shift of the emitted light and the formation of defects which are confined near to the quantum well. A partial broadening of the quantum well could be observed, which is attributed to the outdiffusion of Cd from the active region.