Analysis of Nanocrystal of Porous Silicon with High-Resolution Transmission Electron Microscopy

2013 ◽  
Vol 650 ◽  
pp. 34-38 ◽  
Author(s):  
Jing Mei Lu ◽  
Xuan Cheng

The porous silicon samples were prepared with n(111) Si wafers by electrochemical polarization and their microstructures were characterized by high-resolution transmission electron microscopy (HRTEM). The DigitalMicrograph image processing was used to analyze the HRTEM images. The distorted Si (111) crystal plane was observed on porous silicon and could be distinguished with the Fourier transforming electron diffraction (ED) pattern. Grain boundaries were presented in the HRTEM images where the lattice fringes distortions took place. The anisotropy property could be preserved at a small location area because of the smaller nanocrystals in different directions appeared amorphous in the ED pattern at a larger range.

1995 ◽  
Vol 398 ◽  
Author(s):  
W. Sinkler ◽  
C. Michaelsen ◽  
R. Bormann

ABSTRACTInverse melting of bcc Nb4sCr55 is investigated using transmission electron microscopy, high-resolution TEM and electron diffraction. It is shown that the transformation to the amorphous phase initiates at the bcc grain boundaries. The transformation results in an increase in incoherence, evidenced by a loss of bend contours. Some anisotropy is found in the amorphous phase produced by inverse melting, which is associated in HRTEM with preferentially oriented but discontinuous and distorted fringes. The results are consistent with the production of an amorphous phase by inverse melting.


1999 ◽  
Vol 588 ◽  
Author(s):  
Daisuke Takeuchi ◽  
Hideyuki Watanabe ◽  
Sadanori Yamanaka ◽  
Hideyo Okushi ◽  
Koji Kajimura ◽  
...  

AbstractThe band-A emission (around 2.8 eV) observed in high quality (device-grade) homoepitaxial diamond films grown by microwave-plasma chemical vapor deposition (CVD) was studied by means of scanning cathodoluminescence spectroscopy and high-resolution transmission electron microscopy. Recent progress in our study on homoepitaxial diamond films was obtained through the low CH4/H2 conditions by CVD. These showed atomically flat surfaces and the excitonic emission at room temperature, while the band-A emission (2.95 eV) decreased. Using these samples, we found that the band-A emission only appeared at unepitaxial crystallites (UC) sites, while other flat surface parts still showed the excitonic emission. High-resolution transmission electron microscopy revealed that there were grain boundaries which contained π-bonds in UC. This indicates that one of the origin of the band-A emission in diamond films is attributed to π bonds of grain boundaries.


2011 ◽  
Vol 189-193 ◽  
pp. 1036-1039
Author(s):  
Jing Ling Ma ◽  
Jiu Ba Wen ◽  
Yan Fu Yan

The precipitates of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt %) anode alloy were studied by scanning electron microscopy, X-ray microanalysis, high resolution transmission electron microscopy and selected area electron diffraction analyses in the present work. The results show that the alloy mainly contains hexagonal structure MgZn2 and tetragonal structure Al2CeZn2 precipitates. From high resolution transmission electron microscopy and selected area electron diffraction, aluminium, Al2CeZn2 and MgZn2 phases have [0 1 -1]Al|| [1 -10]Al2CeZn2|| [-1 1 0 1]MgZn2orientation relation, and Al2CeZn2 and MgZn2 phases have the [0 2 -1]Al2CeZn2|| [0 1 -10]MgZn2orientation relation.


1998 ◽  
Vol 553 ◽  
Author(s):  
C. Reich ◽  
M. Conrad ◽  
F. Krumeich ◽  
B. Harbrecht

AbstractThe dodecagonal (dd) quasicrystalline tantalum telluride dd Ta1.6Te and the crystalline approximant Ta97Te60 have been modified by partly replacing tantalum by vanadium. The impact of the substitution on the structures has been studied by X-ray and electron diffraction and by high-resolution transmission electron microscopy. The layered-type approximant structure of Ta83V14Te60 was determined by single crystal X-ray means. The partitioning of vanadium on 21 out of 29 crystallographically inequivalent metal sites is referred to, but not controlled by the Dirichlet domain volume available at the sites. A HRTEM projection of dd (Ta, V)1.6Te onto the dodecagonal plane is analysed with respect to the arrangement of (Ta, V)151Te74 clusters on the vertices of an irregular aperiodic square-triangle tiling, the edge length of which corresponds to the distance between the centres of two such clusters. The clusters comprise about 1 nm thick corrugated lamellae which are periodically stacked by weak Te-Te interactions.


2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  

AbstractA new method for synthesis of 2D nanocrystals in water was proposed. The use of perfluorothiophenolate ions as surfactant allowed us to produce 2D single-crystal nanosheets of CaS at pH=9 and flat nanocrystals of PbS at pH=9 at room temperature. Mesocrystalline nanobelts of CdS and mesocrystals of PbS were obtained at pH=3–5 and pH=10–12, respectively. Morphology, structure and chemical composition of nanoparticles were characterized by high-resolution transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. A mechanism of nanoparticles formation was discussed.


2005 ◽  
Vol 884 ◽  
Author(s):  
Carmen M. Andrei ◽  
John C. Walmsley ◽  
Randi Holmestad ◽  
Gianluigi A. Botton ◽  
Sesha S. Srinivasan ◽  
...  

AbstractTi doped NaAlH4 hydride is proposed as a reversible hydrogen storage material. In this work, the microstructure of NaAlH4 with 2% TiCl3 additive was studied after 5 hydrogen cycles using a combination of transmission electron microscopy (TEM) techniques including energy dispersive spectroscopy (EDS) X-ray analysis. Selected area diffraction and high-resolution (HR) imaging confirmed the presence of the NaH phase in the material. Electron diffraction was dominated by Al. HRTEM showed the presence of edge dislocations, which might influence the hydrogen diffusivity process in these materials.


2012 ◽  
Vol 18 (S5) ◽  
pp. 3-4 ◽  
Author(s):  
M. C. Proença ◽  
J. F. Moura Nunes ◽  
A. P. Alves de Matos

Automatic image processing of transmission electron microscopy images (TEM) is a utopia often pursued, considering the thousands of images necessary to ensure a high resolution 3D reconstruction of virus particles or other macromolecular machines.


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