The Growth of Ni Overlayers on Au(100) Buffers Deposited on GaAs(100) and MgO(100) Substrates.

1991 ◽  
Vol 237 ◽  
Author(s):  
B. Gilles ◽  
J. Eymery ◽  
A. Marty ◽  
J. C. Joud ◽  
A. Chamberod
Keyword(s):  
Room Temperature ◽  
Stacking Faults ◽  
Grazing Incidence ◽  
Auger Spectroscopy ◽  
Layer By Layer ◽  
Nucleation Layer ◽  
Grazing Incidence Diffraction ◽  
Auger Signal ◽  
Layer Mode ◽  
Atomic Mixing

ABSTRACTHigh quality single-crystal Au(100) buffers have been grown on GaAs(100) or MgO(100) substrates via a thin bcc Fe(100) nucleation layer. Using RHEED, LEED and Auger spectroscopy the growth of Ni overlayers at room temperature was observed to follow an epitaxial layer-by-layer mode for 2 monolayers, after which islanding occured. Detailed analysis of the Auger signal reveals that atomic mixing appears within the first completed layer. Grazing incidence diffraction has been used to investigate the structure of 5–10 nm films. A mixture of (100) and (110) grains have been characterized; the latter orientation shows a large number of stacking faults along the [111] direction in agreement with the Au[001] direction.

Hysteresis loop shift behavior of CoFeSiB amorphous ribbons

2009 ◽  
Vol 24 (4) ◽  
pp. 1607-1610 ◽  
Author(s):  
J. He ◽  
L. Zhou ◽  
D.L. Zhao ◽  
X.L. Wang
Keyword(s):  
Exchange Bias ◽  
Room Temperature ◽  
Magnetic Domain ◽  
Zero Point ◽  
Grazing Incidence ◽  
Ambient Atmosphere ◽  
X Ray ◽  
Grazing Incidence Diffraction ◽  
Shift Behavior ◽  
Induced Magnetic Anisotropy

Exchange bias phenomena of amorphous CoFeSiB ribbons have been probed at room temperature. The dramatic loop shift away from zero point occurred when the ribbons were annealed in ambient atmosphere with longitudinal field. The possible crystalline phases grown in our ribbons are discussed based on the grazing incidence diffraction and energy dispersive x-ray spectroscopy. The magnetic domain configuration of ribbon surface was also observed to make clear the dependence of bias behavior on the induced magnetic anisotropy in the ribbon. A simple phenomenological explanation was given to discuss the exchange bias in ribbons.

Epitaxial Growth of GaN Films Produced by ECR-Assisted MBE

1995 ◽  
Vol 395 ◽  
Author(s):  
T.D. Moustakas
Keyword(s):  
Epitaxial Growth ◽  
Molecular Beam ◽  
Electron Cyclotron Resonance ◽  
Stacking Faults ◽  
Surface Roughening ◽  
Layer By Layer ◽  
Mg Doping ◽  
Nucleation Sites ◽  
Layer Mode ◽  
Mg Doped

ABSTRACTThe epitaxial growth of wurtzite and zincblende GaN on (0001) sapphire and (001) Si by the Electron Cyclotron Resonance-assited Molecular Beam Epitaxy (ECR-MBE) method is discussed. We show that films can be grown in the layer-by-layer mode when growth occurs in Ga-rich regime. Surface roughening mechanisms are addressed. The similarity of photoluminescence data of Mg-doped wurtzite GaN films with those of undoped zincblende GaN films suggests that Mg doping facilitates the formation of stacking faults in the wurtzite structure which are nucleation sites for zincblende domains.

Hetero-Epitaxial Defects and Optical Characteristics of SiCGe Layers Grown on 6H-SiC Substrate

2010 ◽  
Vol 663-665 ◽  
pp. 445-448
Author(s):  
Tao Lin ◽  
Nan Lin ◽  
Lian Bi Li ◽  
Chen Yang ◽  
Hong Bin Pu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Optical Transmission ◽  
Optical Characteristics ◽  
Layer By Layer ◽  
Transmission Spectra ◽  
Photoluminescence Spectra ◽  
Peak Wavelength ◽  
Room Temperature Photoluminescence ◽  
Layer Mode ◽  
Optical Transmission Spectra

By means of SEM, TEM, UV-VIS optical transmission spectra and photoluminescence spectra tests, hetero-epitaxial defects and optical characteristics of SiCGe layers grown on 6H-SiC substrate were studied. SEM and TEM images have shown that the SiCGe were grown in layer-by-layer mode with APD and DPB defects which were caused by the thermal and lattice mismatches between SiCGe and SiC. Transmission spectra results have shown the calculated band gap of the SiCGe layer was 2.31eV. Room temperature photoluminescence spectra have shown that the peak wavelength and the FWHM of SiCGe layer were closely related to its Ge contents and the hetero-epitaxial defects.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

The Growth Of Thin Ti Films on Si(111)-(7×7) Surfaces

1995 ◽  
Vol 402 ◽  
Author(s):  
Adli A. Saleh ◽  
D. Peterson
Keyword(s):  
Room Temperature ◽  
Growth Morphology ◽  
Continuous Film ◽  
Temperature Growth ◽  
Low Energy Electron Diffraction ◽  
Auger Signal ◽  
Low Energy Electron ◽  
Atomically Flat ◽  
Signal Time ◽  
Ti Films

AbstractA study of the room-temperature growth of ultrathin Ti films (up to 7 ML) on clean and atomically flat Si(111)- (7×7) surfaces using Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) is presented. The variations in the Auger signal due to Si L2.3VV with binding energy of 92 eV are used to model the growth morphology of this system. These measurements indicate the growth of an initial disordered and continuous Ti film of up to 1.6 ML in thickness, where the LEED pattern completely disappears and the Si Auger signal is strongly attenuated. As more Ti is deposited, this is followed by the disintegration of the continuous film and the formation of an intermixed Ti/Si film. This is evidenced by a change in the slope of the Auger signal time (AST) plot, and the reappearance of the LEED pattern. The modification in the overlayer composition for films thicker than 1.6 ML is confirmed by a change in the Si L2.3VV Auger peak that resembles the peak shape due to TiSi2.

Effect of the Nucleation Layer on TiO2 Nanoflowers Growth via Solvothermal Synthesis

2012 ◽  
Vol 1479 ◽  
pp. 95-100
Author(s):  
Oscar A. Jaramillo ◽  
Reshmi Raman ◽  
Marina E. Rincón
Keyword(s):  
Solvothermal Synthesis ◽  
Room Temperature ◽  
Active Surface ◽  
Dip Coating ◽  
Fixed Number ◽  
Active Surface Area ◽  
Nucleation Layer ◽  
Sensing Properties ◽  
Nucleation Sites ◽  
Ethanol Sensing

ABSTRACTTiO2 nanoflowers were obtained on modified ITO substrates by solvothermal synthesis. Surface modification was achieved with a layer of TiO2 seeds/nucleus obtained by dip-coating at various pH and dip cycles. Field emission scanning electron microscopy results indicated that at all nucleation conditions there was a dual population of TiO2 nanoparticles and nanoflowers. For a particular pH, the effect of increasing the number of dips was to increase the size and number of the nanoflowers, whereas for a fixed number of dips, the increase in pH causes a decrease in nanoflower population. The comparison with solvothermal films obtained on unmodified substrates indicates that TiO2 nanoflowers grew up on the nucleation sites. These microstructural changes determine the active surface area and sensing properties of the solvothermal films. At room temperature, no evidence of superior ethanol sensing properties was found for TiO2 nanoflowers, which show larger resistivity than TiO2 nanoparticles.

scholarly journals Synthesis of CdS nanocrystals in polymeric films studied by in-situ GID and GISAXS

2015 ◽  
Vol 1810 ◽  
Author(s):  
Tiziana Di Luccio ◽  
Dina Carbone ◽  
Silvia Masala ◽  
Karthik Ramachandran ◽  
Julie Kornfield
Keyword(s):  
Hexagonal Lattice ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Polymeric Films ◽  
Diffraction Intensity ◽  
Cds Nanocrystals ◽  
Grazing Incidence Diffraction ◽  
Angle Scattering ◽  
Precursor Structure

ABSTRACTIn this work, we describe the synthesis of CdS nanocrystals in thin polymeric films by in-situ Grazing Incidence Diffraction (GID) and Grazing Incidence Small Angle Scattering (GISAXS). The 2D GISAXS patterns indicate how the precursor structure is altered as the temperature is varied from 25°C to 300°C. At 150°C, the CdS nanocrystals start to arrange themselves in a hexagonal lattice with a lattice parameter of 27 Å. The diffraction intensity from the hexagonal lattice reaches a maximum at 170°C and decreases steadily upon further heating above 220°C indicating loss of symmetry. Correspondingly, the GID scans at 170°C show strong crystalline peaks from cubic CdS nanocrystals that are about 2 nm size. The results indicate that a temperature of 170°C is sufficient to synthesize CdS nanocrystals without degradation of the polymer matrix (Topas) in thin films (about 30nm).

Aging Response in Selective Laser Melted AlSi10Mg Alloy as Function of Distance from the Substrate Plate

2021 ◽  
Vol 1016 ◽  
pp. 476-480
Author(s):  
Emanuele Ghio ◽  
Emanuela Cerri
Keyword(s):  
Vickers Microhardness ◽  
Vertical Axis ◽  
Heat Treatments ◽  
Layer By Layer ◽  
Laser Melting ◽  
Aging Response ◽  
Layer Mode ◽  
Substrate Plate ◽  
Strength And Ductility ◽  
Scanning Electron

Selective Laser Melting (SLM) builds a metallic part in a layer-by-layer mode with growth occurring along the vertical axis. Metallic powder layers are melted by a laser beam by programmed scan sequences inducing specific mechanical properties in the as-built samples according to process parameters. Post heat treatments are usually performed to optimise the mechanical behaviour. In this work, the effects induced by heat treatments at 175°, 200° and 225°C on SLMed bars of Al10SiMg were investigated as function of distance from the substrate plate. The bars were 300 mm height and in the as-built condition, Vickers microhardness and tensile strength decreased along the built direction, while the elongation increased from the bottom to the top of the billet. After heat treatments, Vickers microhardness resulted lower of 10HV at the top of the bar compared to its bottom in contact with the hot substrate; microhardness decreased with time at constant temperature compared to the as-built. Tensile properties showed variations of 50 MPa and 1% elongation between the top and the bottom of the billet when aging was performed at 175°C for 4h; the strength and ductility gradients were reduced to 20 MPa and 0,5% respectively by increasing the aging time to 6h. Microstructure investigations performed by scanning electron microscopy confirmed the different evolution of Silicon particles and precipitated particles at different height of the bars.

New Perovskite Nanomaterials and Their Integrations into High-k Dielectrics

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000072-000077
Author(s):  
Minoru Osada ◽  
Takayoshi Sasaki
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Bottom Electrode ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Layered Perovskite ◽  
Layer By Layer ◽  
High K ◽  
High K Dielectric ◽  
High Dielectric

We report on a bottom-up manufacturing for high-k dielectric films using a novel nanomaterial, namely, a perovskite nanosheet (LaNb2O7) derived from a layered perovskite by exfoliation. Solution-based layer-by-layer assembly of perovskite nanosheets is effective for room-temperature fabrication of high-k nanocapacitors, which are directly assembled on a SrRuO3 bottom electrode with an atomically sharp interface. These nanocapacitors exhibit high dielectric constants (k &gt; 50) for thickness down to 5 nm while eliminating problems resulting from the size effect. We also investigate dielectric properties of perovskite nanosheets with different compositions (LaNb2O7, La0.95Eu0.05Nb2O7, and Eu0.56Ta2O7) in order to study the influence of A- and B-site modifications on dielectric properties.

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