Search results for "Aluminium compounds"

showing 3 items of 3 documents

Growth and optical characterization of indirect-gap AlxGa1−xAs alloys

1999

Nonintentionally doped AlxGa1−xAs layers with 0.38 x 0.84 were grown on (100) GaAs substrates by liquid phase epitaxy (LPE) under near-equilibrium conditions. The crystalline quality of the samples was studied by photoluminescence at 2 K and room temperature Raman spectroscopy. The peculiar behavior in the photoluminescence intensities of the indirect bound exciton line and the donor–acceptor pair transition is explained from the evolution of the silicon donor binding energy according to the aluminum composition. It was also possible to observe the excitonic transition corresponding to the AlxGa1−xAs/GaAs interface, despite the disorder and other factors which are normally involved when gro…

PhotoluminescenceMaterials scienceIII-V semiconductorsSiliconExcitonBinding energyGeneral Physics and Astronomychemistry.chemical_elementBinding energyEpitaxyMolecular physicssymbols.namesakePhonon spectraLiquid phase epitaxial growth:FÍSICA [UNESCO]PhotoluminescenceAluminium compoundsX-ray absorption spectroscopyGallium arsenide Semiconductor growthImpurity statesDopingUNESCO::FÍSICASemiconductor epitaxial layersCrystallographychemistrysymbolsPhotoluminescence ; Binding energy ; Raman spectra ; III-V semiconductors ; Aluminium compounds ; Gallium arsenide Semiconductor growth ; Liquid phase epitaxial growth ; Semiconductor epitaxial layers ; Impurity states ; Excitons ; Phonon spectraExcitonsRaman spectraRaman spectroscopy
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Residual strain effects on the two-dimensional electron gas concentration of AlGaN/GaN heterostructures

2001

Ga-face AlGaN/GaN heterostructures with different sheet carrier concentrations have been studied by photoluminescence and Raman spectroscopy. Compared to bulk GaN, an energy shift of the excitonic emission lines towards higher energies was observed, indicating the presence of residual compressive strain in the GaN layer. This strain was confirmed by the shift of the E2 Raman line, from which biaxial compressive stresses ranging between 0.34 and 1.7 GPa were deduced. The spontaneous and piezoelectric polarizations for each layer of the heterostructures have been also calculated. The analysis of these quantities clarified the influence of the residual stress on the sheet electron concentratio…

Electron densityTwo-dimensional electron gasMaterials sciencePhotoluminescenceIII-V semiconductorsAluminium compounds ; Gallium compounds ; III-V semiconductors ; Wide band gap semiconductors ; Semiconductor heterojunctions ; Two-dimensional electron gas ; Electron density ; Internal stresses ; Photoluminescence ; Raman spectra ; Excitons ; Interface states ; Piezoelectric semiconductors ; Dielectric polarisationExcitonAnalytical chemistryGeneral Physics and AstronomyDielectric polarisationMolecular physicsCondensed Matter::Materials Sciencesymbols.namesakeResidual stress:FÍSICA [UNESCO]Emission spectrumPiezoelectric semiconductorsPhotoluminescenceAluminium compoundsUNESCO::FÍSICAWide-bandgap semiconductorGallium compoundsHeterojunctionInterface statesWide band gap semiconductorssymbolsExcitonsRaman spectraSemiconductor heterojunctionsRaman spectroscopyInternal stressesElectron density
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Temperature dependence of the E2h phonon mode of wurtzite GaN/AlN quantum dots

2008

Raman scattering has been used to study the temperature dependence of the frequency and linewidth of the E2h phonon mode of GaN/AlN quantum dot stacks grown on 6H-SiC. The evolution of the nonpolar phonon mode was analyzed in the temperature range from 80 to 655 K for both quantum dots and barrier materials. The experimental results are interpreted by comparison with a model that takes into account symmetric phonon decay and the different thermal expansions of the constituents of the heterostructure. We find a small increase in the anharmonic parameters of the phonon modes in the heterostructure with respect to bulk. jorbumar@alumni.uv.es Alberto.Garcia@uv.es Ana.Cros@uv.es

III-V semiconductorsMaterials scienceCondensed matter physicsPhononUNESCO::FÍSICAGallium compoundsGeneral Physics and AstronomyHeterojunctionAluminium compounds ; Gallium compounds ; III-V semiconductors ; Phonons ; Raman spectra ; Semiconductor quantum dots ; Thermal expansionAtmospheric temperature rangeCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCondensed Matter::Materials Sciencesymbols.namesakeLaser linewidth:FÍSICA [UNESCO]Quantum dotsymbolsPhononsSemiconductor quantum dotsRaman spectraThermal expansionRaman spectroscopyAluminium compoundsRaman scatteringWurtzite crystal structureJournal of Applied Physics
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