Mismatch and chemical composition analysis of vertical InxGa1−xAs quantum-dot arrays by transmission electron microscopy

2001 ◽  
Vol 78 (24) ◽  
pp. 3830-3832 ◽  
Author(s):  
Qi Zhang ◽  
Jing Zhu ◽  
Xiaowei Ren ◽  
Hongwei Li ◽  
Taihong Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
Quantum Dot ◽  
Composition Analysis ◽  
Transmission Electron ◽  
Chemical Composition Analysis

scholarly journals Chemical composition, anatomy, lignin distribution, and cell wall structure of Malaysian plant waste fibers

BioResources ◽  
2006 ◽  
Vol 1 (2) ◽  
pp. 220-232 ◽  
Author(s):  
H. P. S. Abdul Khalil ◽  
M. Siti Alwani ◽  
A. K. Mohd Omar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Chemical Composition ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Anatomical Characteristics ◽  
Lignin Distribution ◽  
Transmission Electron ◽  
Palm Frond

The chemical composition, anatomical characteristics, lignin distribution, and cell wall structure of oil palm frond (OPF), coconut (COIR), pine-apple leaf (PALF), and banana stem (BS) fibers were analyzed. The chemical composition of fiber was analyzed according to TAPPI Methods. Light microscopy (LM) and transmission electron microscopy (TEM) were used to observe and determine the cell wall structure and lignin distribution of various agro-waste fibers. The results revealed differences in anatomical characteristics, lignin distributions, and cell wall structure of the different types of fibers investigated. Nevertheless, transmission electron microscopy (TEM) micrographs have confirmed that the well wall structure, in each case, could be described in terms of a classical cell wall structure, consisting of primary (P) and secondary (S 1 , S 2 , and S 3 ) layers.

scholarly journals Transmission Electron Microscopy of Vertically Stacked ErAs-InAs Semimetal -Quantum Dot Nanocomposite Heterostructures Grown on GaAs(001) Substrates

2017 ◽  
Vol 23 (S1) ◽  
pp. 1524-1525
Author(s):  
Krishnamurthy Mahalingam ◽  
Yuanchang Zhang ◽  
Kurt Eyink ◽  
Joseph Peoples ◽  
Brittany Urwin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dot ◽  
Transmission Electron

The Microstructure of AlSi7Mg Alloy in as Cast Condition

2015 ◽  
Vol 229 ◽  
pp. 3-10 ◽  
Author(s):  
Bartłomiej Dybowski ◽  
Bogusława Adamczyk-Cieślak ◽  
Kinga Rodak ◽  
Iwona Bednarczyk ◽  
Andrzej Kiełbus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
Energy Dispersive Spectrometry ◽  
Intermetallic Phases ◽  
Transmission Electron ◽  
Alloy Microstructure ◽  
Cast Condition ◽  
Scanning Electron

The complex microstructure of as-cast AlSi7Mg alloy has been investigated. Microstructure observations were done using light microscopy, scanning electron microscopy and transmission electron microscopy. Chemical composition of the microstructure constituents was investigated by means of energy dispersive spectrometry, conducted both during SEM and STEM investigations. Selected area diffraction was used to identify the phases in the alloy. Microstructure of the alloy in the as-cast condition consists of Al-Si eutectic and intermetallic phases in the interdendritic regions. These are: Mg2Si, α-AlFeMnS, β-AlFeSi and π-AlFeSiMg phases. What is more, number of fine precipitates were found within the α-Al dendrites. Only the occurrence of U1 (MgAl2Si2) phase has been confirmed.

Atomic Force Microscopy and Transmission Electron Microscopy Study of Self-Organized Ordering in Vertically Aligned PbSe Quantum Dot Superlattices

2001 ◽  
Vol 696 ◽  
Author(s):  
A. Raab ◽  
G. Springholz ◽  
R. T. Lechner ◽  
I. Vavra ◽  
H. H. Kang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Quantum Dot ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Ordering ◽  
Spacer Thickness

AbstractSelf-organized lateral ordering is studied for PbSe/Pb1-xEuxTe quantum dot superlattices as a function of spacer thickness using atomic force microscopy and transmission electron microscopy. It is found that a pronounced hexagonal lateral ordering tendency exist not only for fcc-stacked superlattices but also for those with vertical dot alignment. For the latter case, a best in-plane ordering is observed for Pb1-xEuxTe spacer thicknesses around 160 Å. This is accompanied by a pronounced narrowing of the size distribution to values as low as ±8%. The resulting in-plane dot separations and dot densities are tunable by changes in spacer thickness. Similar marked changes are also found for PbSe dot shape as well as the dot sizes. This provides additional means for the tuning of the optical and electronic properties of the dots.

Determination of the Quantum Dot Band Gap Dependence on Particle Size from Optical Absorbance and Transmission Electron Microscopy Measurements

ACS Nano ◽  
2012 ◽  
Vol 6 (10) ◽  
pp. 9021-9032 ◽  
Author(s):  
Doris Segets ◽  
J. Matthew Lucas ◽  
Robin N. Klupp Taylor ◽  
Marcus Scheele ◽  
Haimei Zheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Quantum Dot ◽  
Band Gap ◽  
Optical Absorbance ◽  
Transmission Electron

Quantitative Structure Analysis of Nano-sized Materials by Transmission Electron Microscopy

2009 ◽  
Vol 1184 ◽  
Author(s):  
Wolfgang Neumann ◽  
Holm Kirmse ◽  
Ines Häeusler ◽  
Changlin Zheng ◽  
Anna Mogilatenko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Composition ◽  
Soft Magnetic Materials ◽  
Electron Holography ◽  
Quantitative Structure ◽  
Soft Magnetic ◽  
Transmission Electron ◽  
Potential Applicability

AbstractNanostructured materials from almost all classes of materials are of great interest because the reduced dimensionality may drastically change the physical properties. In general, these properties are a function of size, shape, arrangement and chemical composition of the nano-sized materials. Transmission electron microscopy (TEM) is a powerful tool to get a detailed insight into the material characteristics. To correlate microstructure as well as microchemistry and materials properties the various TEM techniques for imaging, diffraction and spectroscopy have to be combined. The potential applicability of quantitative TEM will be demonstrated for different nano-sized objects, particularly for semiconductor islands, nanowires, quantum dots and for soft magnetic materials. The classical diffraction contrast method of conventional TEM is applied to analyse the size, shape and arrangement of nano-sized structures, where a quantitative analysis often requires image simulations of diffraction contrast for theoretical structure models. An alternative and powerful method is the three-dimensional reconstruction of the shape from two-dimensional phase mapping by means of electron holography. This reqires the exact calculation of the mean inner potential of the specimen. Quantitative high-resolution transmission electron microscopy (qHRTEM) has to be applied to analyse structure and chemical composition on an atomic scale of magnitude. Particularly the application of aberration-corrected HRTEM offers new possibilities for quantitative structure analysis due to a contrast transfer by means of negative spherical aberration imaging (NCSI) and the resulting strong suppression of image delocalisation effects. An example for quantitative composition analysis will be demonstrated for ternary semiconductor quantum structures by means of a combined analysis of dark-field imaging and qHRTEM. The results will be compared with analytical TEM data (energy-dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS), and energy-filtered TEM (EFTEM)). The retrieval of chemical information with atomic resolution will be illustrated for III-V semiconductor nanostructures using STEM (scanning TEM) Z-contrast imaging. The correlation of structure and magnetic properties of soft magnetic materials will be demonstrated by combined application of Lorentz microscopy and electron holography. The potential applicability of the different quantitative TEM methods will be shown for following systems:(i) (Si,Ge) islands(ii) ZnTe and (Zn,Mn)Te nanowires(iii) Ga(As,Sb) quantum dots (QDs) on GaAs substrate(iv) nc softmagnetic FeCo alloysThe possibilities and limitations of the various methods applied will be critically evaluated.

scholarly journals Growth Mechanism of Periodic-Structured MoS2 by Transmission Electron Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 135
Author(s):  
Arvind Mukundan ◽  
Yu-Ming Tsao ◽  
Sofya B. Artemkina ◽  
Vladimir E. Fedorov ◽  
Hsiang-Chen Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Mechanism ◽  
Large Scale ◽  
Periodic Structures ◽  
Chemical Vapor ◽  
Composition Analysis ◽  
Transmission Electron ◽  
Growth Phenomenon ◽  
Periodic Growth

Molybdenum disulfide (MoS2) was grown on a laser-processed periodic-hole sapphire substrate through chemical vapor deposition. The main purpose was to investigate the mechanism of MoS2 growth in substrate with a periodic structure. By controlling the amount and position of the precursor, adjusting the growth temperature and time, and setting the flow rate of argon gas, MoS2 grew in the region of the periodic holes. A series of various growth layer analyses of MoS2 were then confirmed by Raman spectroscopy, photoluminescence spectroscopy, and atomic force microscopy. Finally, the growth mechanism was studied by transmission electron microscopy (TEM). The experimental results show that in the appropriate environment, MoS2 can be successfully grown on substrate with periodic holes, and the number of growth layers can be determined through measurements. By observing the growth mechanism, composition analysis, and selected area electron diffraction diagram by TEM, we comprehensively understand the growth phenomenon. The results of this research can serve as a reference for the large-scale periodic growth of MoS2. The production of periodic structures by laser drilling is advantageous, as it is relatively simpler than other methods.

Design of 2D-nanocrystals in water: preparation, structure and functionalization

2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
High Resolution ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Room Temperature ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron

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.

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