0000000000543744

AUTHOR

Maria Tchernycheva

showing 3 related works from this author

Indium surfactant effect on AlN/GaN heterostructures grown by metal-organic vapor-phase epitaxy: Applications to intersubband transitions

2006

We report on a dramatic improvement of the optical and structural properties of AlN/GaN multiple quantum wells (MQWs) grown by metal-organic vapor-phase epitaxy using indium as a surfactant. This improvement is observed using photoluminescence as well as x-ray diffraction. Atomic force microscopy shows different surface morphologies between samples grown with and without In. This is ascribed to a modified relaxation mechanism induced by different surface kinetics. These improved MQWs exhibit intersubband absorption at short wavelength (2 mu m). The absorption linewidth is as low as 65 meV and the absorption coefficient is increased by 85%.

GaN/AlN quantumMaterials sciencePhotoluminescencePhysics and Astronomy (miscellaneous)business.industrySUPERLATTICESSuperlatticeMULTIPLE-QUANTUM WELLSMU-Mchemistry.chemical_elementquantum dotsHeterojunctionRELAXATIONGallium nitrideEpitaxyLAYERSGANchemistryQuantum dotOptoelectronicsbusinessAbsorption (electromagnetic radiation)Quantum wellIndium
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Nitride-based heterostructures grown by MOCVD for near- and mid-infrared intersubband transitions

2007

Intersubband (lSB) optical absorption in different nitride-based heterostructures grown by metal-organic chemical vapour deposition (MOCVD) is reported. The role of indium in AlInN/GaN multi-quantum wells (MQWs) is investigated. At high concentration (15%) AlInN is quasi lattice-matched to GaN and no cracks appear in the structure. At very low indium concentration (similar to 2%) the material quality is improved without decreasing the ISB transition wavelength with respect to the case of indium-free structures. Different mechanisms of strain relaxation in pure and 2% indium-doped AlN/GaN MQW structures are also investigated. ISB transition wavelengths of 2 urn for AlN/GaN MQWs, and 3 mu n f…

Materials scienceAbsorption spectroscopyCondensed matter physicsbusiness.industryMULTIPLE-QUANTUM WELLSMU-MInfrared spectroscopychemistry.chemical_elementHeterojunctionSurfaces and InterfacesChemical vapor depositionNitrideCondensed Matter PhysicsSettore ING-INF/01 - ElettronicaSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialschemistryMaterials ChemistryABSORPTIONOptoelectronicsMetalorganic vapour phase epitaxyElectrical and Electronic EngineeringbusinessIndiumQuantum well
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Mid-infrared intersubband absorption in lattice-matched AlInN/GaN multiple-quantum wells

2005

We report the observation of midinfrared intersubband (ISB) absorption in nearly lattice-matched AlInNGaN multiple-quantum-wells. A clear absorption peak is observed around 3 μm involving transitions from the conduction band ground state to the first excited state. In addition to ISB absorption, photoluminescence experiments were carried out on lattice- matched AlInNGaN single quantum wells in order to determine the spontaneous polarization discontinuity between GaN and Al0.82 In0.18 N compounds. The experimental value is in good agreement with theoretical predictions. Our results demonstrate that the AlInNGaN system is very promising to achieve crack-free and low dislocation density struct…

GaN/AlN quantumPhotoluminescenceMaterials sciencePhysics and Astronomy (miscellaneous)Condensed matter physicsWide-bandgap semiconductorGallium nitridequantum dotsGallium nitrideMolecular physicsCondensed Matter::Materials Sciencechemistry.chemical_compoundchemistryQuantum dotExcited stateGround stateQuantum wellMolecular beam epitaxy
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