SiC NWs Grown on Silicon Substrate Using Fe as Catalyst

2014 ◽  
Vol 806 ◽  
pp. 39-42
Author(s):  
Paola Lagonegro ◽  
Matteo Bosi ◽  
Giovanni Attolini ◽  
Marco Negri ◽  
Sathish Chander Dhanabalan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Temperature ◽  
Silicon Substrate ◽  
Growth Direction ◽  
Carrier Gas ◽  
Sic Nanowires ◽  
Transmission Electron

We report on the synthesis of SiC nanowires (NWs) using iron as catalyst. The NWs were grown on silicon substrate by vapour-liquid-solid (VLS) mechanism with propane and silane as precursors, both 3% diluted in hydrogen, and hydrogen as carrier gas. The growth temperature was 1250°C, to reach the eutectic values of the Si-Fe alloy and to permit the VLS mechanism. The as-grown SiC nanowires were characterized by scanning and transmission electron microscopy. The nanowires are from 30 to 100 nm in diameter and several μm in length, with <111> growth direction.

Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy

2007 ◽  
Vol 26-28 ◽  
pp. 1207-1210
Author(s):  
Hyung Seok Kim ◽  
Ju Hyung Suh ◽  
Chan Gyung Park ◽  
Sang Jun Lee ◽  
Sam Kyu Noh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Potential ◽  
Early Stage ◽  
Compressive Strain ◽  
Potential Gradient ◽  
Growth Direction ◽  
Transmission Electron ◽  
Self Assembled

The microstructure and strain characteristics of self-assembled InAs/GaAs quantum dots (QDs) were studied by using transmission electron microscopy. Compressive strain was induced to uncapped QDs from GaAs substrate and the misfit strain largely increased after the deposition of GaAs cap layer. Tensile strain outside QD was extended along the vertical growth direction; up to 15 nm above the wetting layer. Vertically nonaligned and aligned stacked QDs were grown by adjusting the thickness of GaAs spacer layers. The QDs with a lens-shaped morphology were formed in the early stage of growth, and their apex was flattened by the out-diffusion of In atoms upon GaAs capping. However, aligned QDs maintained their lens-shaped structure with round apex after capping. It is believed that their apex did not flatten because the chemical potential gradient of In was relatively low due to the adjacent InAs QD layers.

Novel Zn-Doped SnO2 Hierarchical Architectures: Facile Synthesis, Structural Characterization and Enhanced Photocatalytic Property

2012 ◽  
Vol 512-515 ◽  
pp. 334-338 ◽  
Author(s):  
Tie Kun Jia ◽  
Fan Zhang ◽  
Xiao Feng Wang ◽  
Wei Min Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Mixed Solvents ◽  
Photocatalytic Property ◽  
Growth Direction ◽  
High Photocatalytic Activity ◽  
Transmission Electron ◽  
Preferential Growth Direction ◽  
Hierarchical Architectures

Zn-doped SnO2 seaflower like hierarchical architectures have been synthesized via a solvothermal synthesis route in the mixed solvents of ethanol and deionized water. The observations of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that Zn-doped SnO2 seaflower like hierarchical architectures were assembled by the nanowires. The preferential growth direction of nanowires was determined based on the analysis of high resolution transmission electron microscopy (HRTEM). The products were also characterized by X-ray diffraction (XRD) and X-photoelectron spectrum (XPS), and the results indicated that Sn4+ ions were successfully substituted by Zn2+. The photocatalytic activity of Zn-doped SnO2 seaflower like hierarchical architectures was evaluated by the degradation of RhB aqueous solution and the results showed that the product had high photocatalytic activity efficiency.

A Simple Route to Ultra Long SiC Nanowires

2007 ◽  
Vol 7 (2) ◽  
pp. 580-583 ◽  
Author(s):  
K. F. Cai ◽  
Q. Lei ◽  
A. X. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Formation Mechanism ◽  
Stacking Faults ◽  
Simple Route ◽  
Sic Nanowires ◽  
Transmission Electron

SiC nanowires are prepared by pyrolysis of hexamethyldisilane (HMDS), at 1200 °C in a flowing Ar atmosphere. The length of the nanowires is in millimeter scale. Transmission electron microscopy observations indicate that the diameters of the SiC nanowires are in the range of about 8 to 120 nm, and that most of the nanowires have numerous stacking faults. The formation mechanism of the nanowires is proposed.

Transmission Electron Microscopy of ZnO Nanotube Arrays Etched from Electrodeposited ZnO Nanorods

2008 ◽  
Vol 8 (12) ◽  
pp. 6306-6309 ◽  
Author(s):  
Jun Su ◽  
Renchao Che ◽  
Guangwei She ◽  
Xiaofeng Duan ◽  
Wensheng Shi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Large Scale ◽  
Zno Nanorods ◽  
Growth Direction ◽  
Nanotube Arrays ◽  
Zno Nanotube ◽  
Transmission Electron ◽  
Zno Nanotubes

Well aligned large-scale ZnO nanorods were produced by a simple eletrodeposited process. Then, ZnO nanotubes arrays were formed via a subsequent etching in alkaline solution. Extensive studies including SEM, TEM, EDX, STEM and EELS indicate that the Zn and O elemental composition of the nanorods was well-proportioned along the whole cross section and the ZnO nanotubes were Zn terminated at (0001) polar surface toward the growth direction.

Influence of The Growth Temperature on The Presence of Composition Inhomogeneities in In0.52Al0.48As Layers Grown by MBE on InP Substrates

1992 ◽  
Vol 263 ◽  
Author(s):  
F. Peiro ◽  
A. Cornet ◽  
A. Hierms ◽  
J.R. Morante ◽  
A. Georgakilas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Critical Temperature ◽  
Growth Temperature ◽  
Stacking Faults ◽  
Threading Dislocations ◽  
Sample Area ◽  
Transmission Electron ◽  
Inp Substrates

ABSTRACTBy using Transmission Electron Microscopy we have studied the presence of composition inhomogeneities in In0.52Al0.48As layers grown on (100) InP. We have found a critical temperature equal to 550°C above which composition inhomogeneities start to appear nonuniformly distributed over the sample area. However, as the growth temperature increases they cover the whole layer. Furtermore, the density of stacking faults and threading dislocations increases for growth temperatures beyond the optimum value of 530°C.

Quantitative Strain and Compositional Studies of InxGa1−xAs Epilayer in a GaAs-based pHEMT Device Structure by TEM Techniques

2014 ◽  
Vol 20 (4) ◽  
pp. 1262-1270 ◽  
Author(s):  
Duggi V. Sridhara Rao ◽  
Ramachandran Sankarasubramanian ◽  
Kuttanellore Muraleedharan ◽  
Thorsten Mehrtens ◽  
Andreas Rosenauer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Electron Mobility Transistor ◽  
Growth Direction ◽  
Indium Content ◽  
Dark Field ◽  
High Electron ◽  
Device Structure ◽  
Channel Layer ◽  
Transmission Electron

AbstractIn GaAs-based pseudomorphic high-electron mobility transistor device structures, strain and composition of the InxGa1−xAs channel layer are very important as they influence the electronic properties of these devices. In this context, transmission electron microscopy techniques such as (002) dark-field imaging, high-resolution transmission electron microscopy (HRTEM) imaging, scanning transmission electron microscopy-high angle annular dark field (STEM-HAADF) imaging and selected area diffraction, are useful. A quantitative comparative study using these techniques is relevant for assessing the merits and limitations of the respective techniques. In this article, we have investigated strain and composition of the InxGa1−xAs layer with the mentioned techniques and compared the results. The HRTEM images were investigated with strain state analysis. The indium content in this layer was quantified by HAADF imaging and correlated with STEM simulations. The studies showed that the InxGa1−xAs channel layer was pseudomorphically grown leading to tetragonal strain along the [001] growth direction and that the average indium content (x) in the epilayer is ~0.12. We found consistency in the results obtained using various methods of analysis.

Study of the Origin of Misorientation in GaN Grown by Pendeo-Epitaxy

2002 ◽  
Vol 743 ◽  
Author(s):  
D. N. Zakharov ◽  
Z. Liliental-Weber ◽  
A. M. Roskowski ◽  
S. Einfeldt ◽  
R. F. Davis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dislocation Density ◽  
Growth Temperature ◽  
Threading Dislocations ◽  
Transmission Electron ◽  
Edge Dislocations ◽  
Seed Layers

ABSTRACTGrowth of pendeo-epitaxial (PE) layers introduces misorientation between the seed layers and the overgrown wing layers. The origin of this misorientation has been studied by Transmission Electron Microscopy (TEM) using a set of samples in which subsequent procedures utilized in PE were applied, i.e. growth of GaN template, stripe etching, annealing at the growth temperature of the PE layers and final PE growth. It was shown that etching of seed-stripes did not change the type of defects or their distribution. However, heating to the PE growth temperature drastically modified the surface and V-shaped pits were formed. The surface became smooth again after the PE growth took place. Overgrowth of the V-shaped pits resulted in formation of edge threading dislocations over a seed-stripe region with a dislocation density of 8.0×108 cm−2. Formation of new edge dislocations over the seed can have an influence on the misorientation between the PE grown regions.

Structural characterization of electrodeposited nanophase Ni–Cu alloys

2006 ◽  
Vol 21 (1) ◽  
pp. 45-61 ◽  
Author(s):  
S.K. Ghosh ◽  
A.K. Grover ◽  
G.K. Dey ◽  
U.D. Kulkarni ◽  
R.O. Dusane ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Separation ◽  
Growth Direction ◽  
Pulsed Current ◽  
Modulated Structure ◽  
Cu Alloys ◽  
Transmission Electron ◽  
Deposition Techniques

An investigation of Ni–Cu alloys electrodeposited from aqueous bath, using bothdirect current (dc) and pulsed current (pc) deposition techniques, has revealed many interesting features: A modulated structure with typical layer thickness of 90 and75 nm of copper-rich and nickel-rich layers, respectively, is formed in dc plating. A surprising observation was that the modulation direction was parallel to the substrate, unlike in the case of artificial multilayers wherein it is along the growth direction. No such compositional modulations were observed in pc-plating in the present work. Spinodal phase separation, accompanied by L10 ordering, was found to have occurred in the as deposited samples in both the cases. The size of the deposited crystals in both the cases has been found to be in the range of 2.5–30 nm. Detailed high-resolution transmission electron microscopy has shown that the atomic arrangements are nearly perfect right upto the boundaries of the nanosized grains.

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