Unveiling hidden epitaxial interfaces in novel SnO2/Zn2SnO4 core–shell nanowires with a multi-domain shield via cross-sectional transmission electron microscopy

CrystEngComm ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1895-1902 ◽  
Author(s):  
Bojia Xu ◽  
Baobao Cao

Hidden epitaxial interfaces were revealed via cross-sectional TEM study of novel quasi-hexagonal SnO2/Zn2SnO4 core–shell nanowires.

2021 ◽  
Author(s):  
Janusz Sadowski ◽  
Anna Kaleta ◽  
Serhii Kryvyi ◽  
Dorota Janaszko ◽  
Bogusława Kurowska ◽  
...  

Abstract Incorporation of Bi into GaAs-(Ga,Al)As-Ga(As,Bi) core-shell nanowires grown by molecular beam epitaxy is studied with transmission electron microscopy. Nanowires are grown on GaAs(100) substrates with Au-droplet assisted mode. Bi-doped shells are grown at low temperature (300 °C) with a close to stoichiometric Ga/As flux ratio. At low Bi fluxes, the Ga(As,Bi) shells are smooth, with Bi completely incorporated into the shells. Higher Bi fluxes (Bi/As flux ratio ~ 4%) led to partial segregation of Bi as droplets on the nanowires sidewalls, preferentially located at the nanowire segments with wurtzite structure. We demonstrate that such Bi droplets on the sidewalls act as catalysts for the growth of branches perpendicular to the GaAs trunks. Due to the tunability between zinc-blende and wurtzite polytypes by changing the nanowire growth conditions, this effect enables fabrication of branched nanowire architectures with branches generated from selected (wurtzite) nanowire segments.


2008 ◽  
Vol 8 (11) ◽  
pp. 5715-5719 ◽  
Author(s):  
Hyoun Woo Kim ◽  
Jong Woo Lee ◽  
Mesfin A. Kebede ◽  
Hyo Sung Kim ◽  
Buddhudu Srinivasa ◽  
...  

We have prepared MgO/Au core–shell nanowires, subsequently demonstrating the fabrication of Au nanotubes by using MgO nanowires as a sacrificial template. The samples were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. MgO nanowires were coated with a conformal layer of Au via sputtering. By etching away the MgO core in aqueous (NH3)2SO4 solution, hollow nanotube-like structures of Au were readily obtained. This approach offers a potentially useful route for the fabrication of a variety of hollow metallic structures.


Nano Letters ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 7238-7246 ◽  
Author(s):  
Chao Zhang ◽  
Dmitry G. Kvashnin ◽  
Laure Bourgeois ◽  
Joseph F. S. Fernando ◽  
Konstantin Firestein ◽  
...  

Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.


Author(s):  
F. Shaapur

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.


Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.


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