Morphogenesis of anisotropic nanoparticles: self-templating via non-classical, fibrillar Cd2Se intermediates

2018 ◽  
Vol 54 (53) ◽  
pp. 7358-7361 ◽  
Author(s):  
Daniel Wurmbrand ◽  
Jörg Wolfram Anselm Fischer ◽  
Rose Rosenberg ◽  
Klaus Boldt
Keyword(s):  
Growth Direction ◽  
Preferential Growth ◽  
Anisotropic Nanoparticles ◽  
Preferential Growth Direction

Semiconductor nanorods nucleate via a fibrillar intermediate that is able to template its own preferential growth direction.

Influence of Time and Temperature on Directional Growth of MoO3

2016 ◽  
Vol 869 ◽  
pp. 1001-1006
Author(s):  
Claudia Ferreira da Silva ◽  
André Lima e Silva ◽  
Francisco Xavier Nobre ◽  
Edson Cavalcanti Silva Filho ◽  
Luiz de Sousa Santos Jr. ◽  
...  
Keyword(s):  
Glacial Acetic Acid ◽  
Molybdenum Trioxide ◽  
Orthorhombic Phase ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
Directional Growth ◽  
Preferential Growth ◽  
X Ray ◽  
Preferential Growth Direction ◽  
Characteristic Modes

Two-dimensional microstructures of molybdenum trioxide (MoO3) were synthesized by heptamolybdate tetrahydrate ammonium acidification, followed by calcination. A solution of the precursor compound heptamolybdate tetrahydrate ammonium acidified to pH 3,5 using glacial acetic acid followed by hydrothermal treatment for 150, 180 and 200 °C for 1, 6 and 12 hours. Then, the intermediate was calcined at 300 °C for varying time 6 and 12h to obtain MoO3. X-ray diffraction revealed that the crystals grew with crystalline structure corresponding to the orthorhombic phase of MoO3 (a-MoO3) as major phase, with a preferential growth direction along the planes (0K0). Raman spectroscopy and IR confirmed the formation of the characteristic modes of molybdenum trioxide for stage found. With Scanning Electron Microscopy (SEM) was possible to observe the formation of nanoplates.

ANISOTROPIC GOLD NANOCRYSTALS: SYNTHESIS AND CHARACTERIZATION

2010 ◽  
Vol 24 (06n07) ◽  
pp. 757-761 ◽  
Author(s):  
R. STIUFIUC ◽  
F. TODERAS ◽  
M. IOSIN ◽  
G. STIUFIUC
Keyword(s):  
Growth Direction ◽  
Preferential Growth ◽  
Gold Nanocrystals ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Preferential Growth Direction ◽  
Phase Images ◽  
Means Of Transmission

In this letter we report on successful preparation and characterization of anisotropic gold nanocrystals bio-synthesized by reduction of aqueous chloroaurate ions in pelargonium plant extract. The nanocrystals have been characterized by means of Transmission Electron Microscopy (TEM), UV-VIS absorption spectroscopy and tapping mode atomic force microscopy (TM-AFM). Using these investigation techniques, the successful formation of anisotropic single nanocrystals with the preferential growth direction along the gold (111) plane has been confirmed. The high detail phase images could give us an explanation concerning the growth mechanism of the nanocrystals.

OPTICAL PROPERTIES OF Ge NANOWIRES GROWN ON SILICON (100) AND (111) SUBSTRATES

2004 ◽  
Vol 832 ◽  
Author(s):  
V. Sharma ◽  
B. V. Kamenev ◽  
L. Tsybeskov ◽  
T. I. Kamins
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Silicon Substrates ◽  
Si Substrate ◽  
Vapor Liquid Solid ◽  
Preferential Growth ◽  
Intensity Dependence ◽  
Si Substrates ◽  
Preferential Growth Direction

ABSTRACTIn this paper, we report Raman Scattering (RS) and photoluminescence (PL) measurements of Ge nanowires (NWs) grown via vapor-liquid-solid (VLS) using chemical vapor deposition silicon substrates consisting of (100) and (111) crystallographic orientations. Ge NWs grown are ∼40 nm in diameter, approximately a micrometer in length, and a sharp narrow Raman peak at ∼300 cm−1 indicates single crystal quality. An absence of SiGe peak in the Raman spectra indicates that SiGe interdiffusion is insignificant for the NW volume. Low temperature PL-intensity-dependence spectra indicate that the observed emission originates at the Ge NW – Si substrate interface, where SiGe intermixing has been detected. This interface is formed differently for (111) and (100) oriented Si substrates due to the <111> preferential growth direction of Ge NWs.

Experimental Analysis of Seed Effect on the Directional Solidification of Sn-Pb Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 343-347
Author(s):  
Long Sun Chao ◽  
Yu Ru Chen ◽  
Fang Chun Wang
Keyword(s):  
Directional Solidification ◽  
Experimental Analysis ◽  
Casting Process ◽  
Growth Direction ◽  
Columnar Growth ◽  
Preferential Growth ◽  
Microstructure Observation ◽  
Preferential Growth Direction ◽  
Mechanical And Physical Properties ◽  
Bottom Portion

In this paper, an experiment model for the directional solidification of Lead/Tin alloy is built and the effects of different-shape seeds on the microstructures on the solidification microstructure are investigated. In a casting process, the temperature and concentration fields will affect the microstructures of materials and this influence is the key point of improving their mechanical and physical properties. It is not easy to control the morphology of solidifying microstructures. The scheme of directional solidification can make the microstructures grow along a fixed direction and it is also the base of single-crystal growth. In the experiment, a poly-grain seed with the same initial concentration of the solidifying casting is used to induce the columnar growth at the bottom portion of the casting, which could avoid the equiaxed growth due to the high undercooling or cooling rate there. In the experimental analysis, we studied the influences of different geometry seeds on the constrained growth, the preferential growth direction of dendrite, the grain size, the temperature gradient, the growth rate, the primary arm spacing and the secondary arm spacing. From the microstructure observation, the adding seed casting reduced the chill-affected and extended the directional solidification zone. This is expected to have the better or more complete structure of directional solidification. Keywords: Directional Solidification, Seed, Heat Transfer and Microstructure

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.

SYNTHESIS AND LUMINESCENCE PROPERTIES OF ZnO:Eu3+ NANOWIRE ARRAYS VIA ELECTRODEPOSITED METHOD

2010 ◽  
Vol 03 (04) ◽  
pp. 285-288 ◽  
Author(s):  
SHIHUA ZHAO ◽  
LEI YANG ◽  
LINGLING WANG ◽  
BENHAI YU ◽  
YUXI CHEN ◽  
...  
Keyword(s):  
Dopant Concentration ◽  
Growth Direction ◽  
Nanowire Arrays ◽  
Sem Images ◽  
Alumina Membranes ◽  
Transmission Electron ◽  
Preferential Growth Direction ◽  
Zno Crystal ◽  
The Fourier Transform ◽  
Xrd Patterns

ZnO:Eu3+ nanowire arrays (NWAs) were prepared using anodic alumina membranes (AAMs) via an electrodeposited method. The XRD patterns, high resolution transmission electron microscopy (HRTEM) and infrared absorption spectra indicate that Eu3+ has entered ZnO crystal lattice. SEM images show that the as-prepared NWAs were embedded in Al2O3 nanotube arrays (NTAs) and the uniform diameters of those nanowires are about 80 nm. The Fourier Transform pattern of the HRTEM shows that the NWAs are single crystals with preferential growth direction along the [0001]. The PL spectra show that the ratio of relative emission intensity of 612 and 597 nm increases with the increase of dopant concentration of Eu3+ . There is no emission peak at 597 nm with the dopant concentration of 10% Eu3+ . The PL results also show that a new UV emission band centered at 306 nm appears.

Study on Cubic GaN Growth on (001) Rutile TiO2 Substrates by ECR-MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
T. Araki ◽  
H. Mamiya ◽  
K. Kitamura ◽  
Y. Nanishi
Keyword(s):  
Electron Cyclotron Resonance ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
Preferential Growth ◽  
X Ray ◽  
Luminescence Peak ◽  
Cubic Gan ◽  
First Time ◽  
Preferential Growth Orientation ◽  
Resonance Plasma

ABSTRACTGaN layers were grown on a (001) rutile TiO2 substrate by electron cyclotron resonance plasma-excited molecular beam epitaxy. For the first time, c-GaN with a preferential growth orientation was obtained. Based on the results from electron diffraction and X-ray diffraction analysis, we found that c-GaN with the growth direction of [110] was grown on the TiO2 substrate. The formation of c-GaN was also confirmed by cathodoluminescence, in which a luminescence peak was observed at 3.24eV.

Crystal orientation and growth anisotropy of YBa2Cu3O6+x fabricated by directional solidification method

1994 ◽  
Vol 9 (6) ◽  
pp. 1350-1356 ◽  
Author(s):  
Y. Nakamura ◽  
K. Furuya ◽  
T. Izumi ◽  
Y. Shiohara
Keyword(s):  
Crystal Orientation ◽  
Three Dimensional ◽  
Growth Direction ◽  
Zone Melting ◽  
Unidirectional Solidification ◽  
Interface Morphology ◽  
Preferential Growth ◽  
Melting Method ◽  
Steady Growth ◽  
Growth Anisotropy

The unidirectional solidification by a zone-melting method was performed to investigate the growth anisotropy of YBa2Cu3O6+x (123) superconductive oxides. Large faceted interfaces were obtained at growth rates lower than 2 mm/h. The three-dimensional interface morphology and the onset of growth were observed. The crystal faces toward the growth direction were revealed to be close to the {112} face, which was selected as the result of the preferential growth. The growth rate of the {100} faces was evaluated to be about 1.5 times faster than that of the {001} faces from the steady growth condition.

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