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Reflection High-energy Electron Diffraction (reflection + high-energy_electron_diffraction)
Selected AbstractsGrowth of magnetite epitaxial thin films by gas flow sputtering and characterization by FMRIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2007Hiroshi Sakuma Member Abstract The growth of magnetite (Fe3O4) epitaxial thin films on MgO substrates were studied by using gas flow sputtering (GFS). Reflection high-energy electron diffraction (RHEED) and atomic force microscopy showed that the surfaces of the films obtained at a substrate temperature Ts of 300 °C and oxygen flow rates FO2 of 0.12 , 0.18 sccm are fairly flat for the film thickness of about 200 nm. The saturation magnetization and resistivity were close to the reported values of Fe3O4 for Ts= 300°C and FO2 = 0.12,0.20sccm. The films obtained at Ts= 300°C and FO2=0.16 and 0.18 sccm showed Verwey transition, which is persuasive evidence of the formation of Fe3O4. The epitaxial relationship of Fe3O4(100)//MgO(100) and Fe3O4[100]//MgO[100] was confirmed by using ferromagnetic resonance (FMR), and the anisotropy constants and magnetization were obtained by the fitting of resonance-field versus applied-field angle curves. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Unintentionally doped InN grown onto an atomically flat AlN intermediate layer using plasma-assisted molecular beam epitaxyPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006K. R. Wang Abstract Unintentionally doped InN has been grown onto an atomically flat AlN intermediate layer on top of the Si(111) substrate using plasma-assisted molecular beam epitaxy (PA-MBE). Though there are lots of micrometer-size indium droplets randomly distributed on the top of the surface, the highest electron mobility of this InN thin film measured at room temperature by van der Pauw method is still higher than 1000 cm2/V s with a carrier concentration of 5,8.9 × 1018 cm,3. A symmetrical X-ray rocking curve is measured and the full-width-at-half-maximum (FWHM) of this sample is 1089 arcsec. In the meantime, the threading dislocation (TD) density of this material is estimated to around 9.8 × 108 cm,2 , 7.5 × 109 cm,2 depending on the probing regions that are studied by the etching technique and field-emission scanning electron microscopy (FE-SEM). (2 × 1) in situ reflection high-energy electron diffraction (RHEED) patterns show that this sample is grown under In-rich environment with possible In-terminated surface. From the FE-SEM pictures which were taken from the samples after 10 minutes etching in hydrochloride, the surface morphology shows In-polarity-like patterns that coincide with those procured in RHEED. To select and grow a high-quality laminated AlN as intermediate layer is believed to be the major step in obtaining this high electron mobility InN thin film on Si substrate. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Self-assembled quantum dot formation induced by surface energy change of a strained two-dimensional layerPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2004Frank Tinjod Abstract To account for the occurrence (or not) of the Stranski-Krastanow (SK) transition (two-dimensional to 3D change of surface morphology) during the epitaxial growth of various lattice-mismatched semiconductor systems, we present a simple equilibrium model taking into account not only the lattice mismatch, but also the dislocation formation energy and the surface energy. It demonstrates the importance of these parameters especially for II,VI systems such as CdTe/ZnTe and CdSe/ZnSe. For II,VIs indeed, as misfit dislocations are easier to form than in III,Vs (such as InAs/GaAs) or IV systems (Ge/Si), the 3D elastic transition is short-circuited by the plastic one. Nevertheless, by lowering surface energy, telluride and selenide quantum dots can also be grown as predicted by our model and as evidenced experimentally by reflection high-energy electron diffraction (RHEED), atomic force microscopy and optical measurements. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Growth of A -plane (11-20) In-rich InGaN on R -plane (10-12) sapphire by RF-MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007M. Noda Abstract Non-polar A -plane (11-20) high In content (In-rich) InGaN was grown on R -plane (10-12) sapphire with an InN template by radio-frequency plasma assisted molecular beam epitaxy (RF-MBE). Nitridation of R -plane sapphire was carried out at 300 °C for 2 hours by RF-nitrogen plasma. A template of A -plane InN was grown at 400 °C. The In-rich InGaN films were then grown at the same temperature on the InN template. We characterized the films using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), scanning electron microscopy (SEM) and photo-luminescence (PL). These results indicated clearly that non-polar In0.71Ga0.29N was successfully obtained with a PL emission at approximately 1.1 eV. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] 1.3 µm high indium content (42.5%) GaInNAs/GaAs quantum wells grown by molecular beam epitaxyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006Zhichuan Niu Abstract High structural and optical quality 1.3 µm GaInNAs /GaAs quantum well (QW) samples with 42.5% indium content were successfully grown by molecular beam epitaxy. The growth of well layers was monitored by reflection high-energy electron diffraction (RHEED). Room temperature photoluminescence (PL) peak intensity of the GaIn0.425NAs/GaAs (6 nm/20 nm) 3QW is higher than, and the full width at half maximum (FWHM) is comparable to, that of In0.425GaAs/GaAs 3QW, indicating improved optical quality due to strain compensation effects by introducing N to the high indium content InGaAs epilayer. The measured (004) X-ray rocking curve shows clear satellite peaks and Pendellösung fringes, suggesting high film uniformity and smooth interfaces. The cross sectional TEM measurements further reveal that there are no structural defects in such high indium content QWs. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Formation and optical properties of Cr-doped CdTe/ZnTe nanostructures on ZnTe substrates by molecular beam epitaxyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2003K. Godo Abstract We study the growth and optical properties of Cr-doped CdTe/ZnTe nanostructures grown on ZnTe (001) substrates by molecular beam epitaxy. In-situ reflection high-energy electron diffraction is used to study the growth processes and strain relaxation behaviors of Cr-doped CdTe quantum dots (QDs). After 4.5,ML deposition, the surface lattice parameter begins to increase remarkably, which indicates that the two-dimensional growth mode is terminated and the CdTe layer grows in a three-dimensional mode. Low temperature photoluminescence spectra of Cr-doped CdTe QDs (Tcr = 900 °C) show a broad emision. With increasing the Cr cell temperature above 1000 °C, the luminescence from CdTe QDs disappears and the broad luminescence at around 1.6 eV becomes dominant. [source] | ||||||||||