Nanoscale characterization of bismuth telluride epitaxial layers by advanced X-ray analysis

2017 ◽  
Vol 50 (2) ◽  
pp. 399-410 ◽  
Author(s):  
Sérgio L. Morelhão ◽  
Celso I. Fornari ◽  
Paulo H. O. Rappl ◽  
Eduardo Abramof
Keyword(s):  
Bismuth Telluride ◽  
Three Dimensional ◽  
Strongly Correlated ◽  
Synchrotron Source ◽  
X Ray ◽  
Force Microscopy ◽  
Area Detector ◽  
Atomic Force ◽  
Nanoscale Characterization ◽  
Recursive Equations

The surface properties of topological insulators are strongly correlated with their structural properties, requiring high-resolution techniques capable of probing both surface and bulk structures at once. In this work, the high flux of a synchrotron source, a set of recursive equations for fast X-ray dynamical diffraction simulation and a genetic algorithm for data fitting are combined to reveal the detailed structure of bismuth telluride epitaxial films with thicknesses ranging from 8 to 168 nm. This includes stacking sequences, thickness and composition of layers in model structures, interface coherence, surface termination, and morphology. The results are in agreement with the surface morphology determined by atomic force microscopy. Moreover, by using X-ray data from a zero-noise area detector to construct three-dimensional reciprocal-space maps, insights into the nanostructure of the domains and stacking faults in Bi2Te3 films are given.

Microstructural Study of a Passivation Layer on GaAs: An Application of X-Ray Reflectivity Under Grazing Angles Using a Synchrotron Source

2003 ◽  
Vol 10 (02n03) ◽  
pp. 373-379 ◽  
Author(s):  
K. E. Crompton ◽  
T. R. Finlayson ◽  
C. Kirchner ◽  
M. Seitz ◽  
U. Klemradt
Keyword(s):  
External Surface ◽  
Synchrotron Source ◽  
Microstructural Study ◽  
X Ray ◽  
Force Microscopy ◽  
Microstructural Parameters ◽  
Atomic Force ◽  
Potential Applications ◽  
Grazing Angles ◽  
Mode Atomic Force Microscopy

X-ray specular reflectivities of GaAs samples passivated with a thin film of (3-mercaptopropyl)-trimethoxysilane (MPT) have been studied using bending-magnet synchrotron radiation. Various preparation procedures covering etching the GaAs, MPT deposition and its baking have been investigated. An oxide film is always observed between the GaAs and MPT films. The microstructural parameters, such as film thickness, density and interfacial roughness (including the external surface), have been determined from appropriate modeling of the reflectivity. The surface roughness has been compared with a direct measurement using tapping-mode atomic force microscopy. The results are discussed with reference to the potential applications of GaAs as a biosensor.

scholarly journals Curcumin Loaded Nanoliposomes Localization by Nanoscale Characterization

2020 ◽  
Vol 21 (19) ◽  
pp. 7276
Author(s):  
Elmira Arab-Tehrany ◽  
Kamil Elkhoury ◽  
Gregory Francius ◽  
Loic Jierry ◽  
Joao F. Mano ◽  
...  
Keyword(s):  
Antioxidative Activity ◽  
Aqueous Solubility ◽  
Phospholipid Membrane ◽  
Hydrophobic Drug ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Nanoscale Characterization ◽  
Uv Visible

Curcumin is a hydrophobic drug gaining growing attention because of its high availability, its innocuity, and its anticancer, antitumoral, and antioxidative activity. However, its poor ‎‎bioavailability in the human body, caused by its low aqueous solubility and fast degradation, ‎‎presents a big hurdle for its oral administration. Here, we used nano-vesicles made of ‎‎phospholipids to carry and protect curcumin in its membrane. Various curcumin amounts were ‎‎encapsulated in the produced phospholipid system to form drug-loaded liposomes. ‎Curcumin’s ‎concentration was evaluated using UV-visible measurements. The maximal ‎amount of curcumin ‎that could be added to liposomes was assessed. Nuclear magnetic ‎resonance (NMR) analyses ‎were used to determine curcumin’s interactions and localization ‎within the phospholipid ‎membrane of the liposomes. X-ray scattering (SAXS) and atomic ‎force microscopy (AFM) ‎experiments were performed to characterize the membrane structure ‎and organization, as well as its ‎mechanical properties at the nanoscale. Conservation of the membrane’s properties is found with ‎the addition of curcumin in various ‎amounts before saturation, allowing the preparation of a ‎defined nanocarrier with desired ‎amounts of the drug.

Differential height characteristics of plasmid and G-wire DNA as determined by AFM

1994 ◽  
Vol 52 ◽  
pp. 1052-1053
Author(s):  
T. C. Marsh ◽  
J. Vesenka ◽  
E. Henderson
Keyword(s):  
Plasmid Dna ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Helical Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimension One

Atomic-Force Microscopy (AFM) has become an effective tool in the three dimensional characterization of biological systems and is capable of Angstrom sensitivity in the vertical dimension. One unresolved dilemma is that the observed height (diameter) of B-DNA being about 10Å, is less than half its x-ray diffraction value. In this paper we attempt to determine the source of this discrepancy by comparing plasmid DNA co-deposited with a novel form of DNA called “G-wires” (Figure 1). G-wires are formed by G-rich sequences. They are composed of G-4 DNA, a quadruple helical structure. X-ray data of G-4 DNA gives a diameter of 27Å, comparable to that expected for B-DNA (20 to 25Å). In the AFM these structures have a significantly greater height (av. = 22 Å) compared to double stranded (av. = 7 Å) or supercoiled B-DNA (av. = 14 Å) (Figure 2). Thus, the apparent height of nucleic acids in the AFM is dependent upon their innate structural characteristics.

Bridging structure and mechanics of three-dimensional porous hydrogel with X-ray ultramicroscopy and atomic force microscopy

RSC Advances ◽  
2015 ◽  
Vol 5 (78) ◽  
pp. 63909-63916 ◽  
Author(s):  
A. Y. Abuelfilat ◽  
Y. Kim ◽  
P. Miller ◽  
S. P. Hoo ◽  
J. Li ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Phase Contrast ◽  
Three Dimensional ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Collective Performance ◽  
Porous Hydrogel

By combining phase contrast X-ray ultramicroscopy and nanoindentation with atomic force microscopy, the mechanics of individual hydrogel pores as well as their collective performance as a scaffold can be modelled and simulated.

scholarly journals Multifractal characterization of epitaxial silicon carbide on silicon

2017 ◽  
Vol 35 (3) ◽  
pp. 539-547
Author(s):  
Ştefan Ţălu ◽  
Sebastian Stach ◽  
Shikhgasan Ramazanov ◽  
Dinara Sobola ◽  
Guseyn Ramazanov
Keyword(s):  
Silicon Carbide ◽  
Surface Condition ◽  
Three Dimensional ◽  
Epitaxial Silicon ◽  
Large Area ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nano Size

AbstractThe purpose of this study was to investigate the topography of silicon carbide films at two steps of growth. The topography was measured by atomic force microscopy. The data were processed for extraction of information about surface condition and changes in topography during the films growth. Multifractal geometry was used to characterize three-dimensional micro- and nano-size features of the surface. X-ray measurements and Raman spectroscopy were performed for analysis of the films composition. Two steps of morphology evolution during the growth were analyzed by multifractal analysis. The results contribute to the fabrication of silicon carbide large area substrates for micro- and nanoelectronic applications.

Nitridation of Substrates With Hydrazine Cyanurate for The Growth of Gallium Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
T. J. Kropewnicki ◽  
P. A. Kohl
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Composition ◽  
Low Temperature ◽  
Surface Morphology ◽  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth

ABSTRACTThe use of purified hydrazine cyanurate as a solid source of hydrazine in the low temperature nitridation of GaAs (100) and (111) and sapphire (0001) is demonstrated. Thenitridated surfaces were analyzed by X-ray Photoelectron Spectroscopy (XPS) for chemical composition and Atomic Force Microscopy for surface morphology. The GaAs surfaces were composed primarily of GaN, GaAs, and Ga2O3, and were as smooth as unprocessed standards. The nitridated sapphire surfaces were composed of A1NxO1-x and exhibited three-dimensional growth for long nitridation times.

Three-dimensional readout of flash x-ray images of living sperm in water by atomic-force microscopy

Science ◽  
1991 ◽  
Vol 252 (5006) ◽  
pp. 691-693 ◽  
Author(s):  
T Tomie ◽  
H Shimizu ◽  
T Majima ◽  
M Yamada ◽  
T Kanayama ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Three Dimensional ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force

Bio-Inspired Evolution of Zinc Oxide-Based Materials Directed by Amino Acids and Peptides.

2005 ◽  
Vol 873 ◽  
Author(s):  
Joachim Bill ◽  
Peter Gerstel ◽  
Rudolf C. Hoffmann ◽  
Lars P. H. Jeurgens ◽  
Peter Lipowsky ◽  
...  
Keyword(s):  
Amino Acids ◽  
Zinc Oxide ◽  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Morphological Aspects ◽  
Atomic Force

AbstractWithin this paper the suitability of amino acids and dipeptides as structure-directing agents is discussed. According to that bio-inspired approach these biomolecules were investigated with respect to the evolution of zinc oxide-based architectures. Those small molecules are able to trigger the morphology of these materials ranging from grain-like via two up to three dimensional features. Besides morphological aspects the structural characterization of these solids by means of electron and atomic force microscopy as well as by photoelectron spectroscopy and X-ray diffraction are discussed in order to extract the function of the biomolecules with regard to the formation of the inorganic phases.

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