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Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/19727

Step-by-step capping and strain state of GaN/AlN quantum dots studied by grazing-incidence diffraction anomalous fine structure

AutorCoraux, J.; Proietti, M. G.; Favre-Nicolin, V.; Renevier, H.; Daudin, B.
Palabras claveGallium compounds
Aluminium compounds
III-V semiconductors
Wide band gap semiconductors
Semiconductor epitaxial layers
Semiconductor quantum dots
Nanostructured materials
X-ray optics
X-ray diffraction
X-ray absorption spectra
Stress analysis
Crystal structure
Fecha de publicaciónmay-2006
EditorAmerican Physical Society
CitaciónPhysical Review - Section B - Condensed Matter 73(20): 205343.1-205343.8 (2006)
ResumenThe investigation of small-size embedded nanostructures, by a combination of complementary anomalous diffraction techniques, is reported. GaN quantum dots (QD's), grown by molecular beam epitaxy in a modified Stranski-Krastanow mode, are studied in terms of strain and local environment, as a function of the AlN cap layer thickness, by means of grazing-incidence anomalous diffraction. That is, the x-ray photon energy is tuned across the Ga absorption K edge which makes diffraction chemically selective. Measurement of hkl scans, close to the AlN (300) Bragg reflection, at several energies across the Ga K edge, allows the extraction of the Ga partial structure factor, from which the in-plane strain of GaN QD's is deduced. From the fixed-Q energy-dependent diffracted intensity spectra, measured for diffraction-selected isostrain regions corresponding to the average in-plane strain state of the QD's, quantitative information regarding the composition and out-of-plane strain has been obtained. We recover the in-plane and out-of-plane strains in the dots. The comparison to the biaxial elastic strain in a pseudomorphic layer indicates a tendency to an overstrained regime.
Descripción8 pages, 11 figures, 1 table.-- PACS number(s): 61.10.Nz, 61.10.Ht, 61.10.Eq, 61.46.-w
Versión del editorhttp://dx.doi.org/10.1103/PhysRevB.73.205343
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