High-Quality, Smooth Fe3O4 Thin Films on Si By Controlled Oxidation of Fe in CO/CO2

2012 ◽  
Vol 1430 ◽  
Author(s):  
Fengyuan Shi ◽  
Hua Xiang ◽  
M. S. Rzchowski ◽  
Y. A. Chang ◽  
P.M. Voyles
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Thin Films ◽  
Scanning Transmission Electron Microscopy ◽  
Defect Density ◽  
Second Phase ◽  
High Quality ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

ABSTRACTWe fabricated Fe3O4 thin films on TiN buffered Si by CO/CO2 oxidation at 160 °C. The easy saturation of the magnetization at high magnetic field and high resolution scanning transmission electron microscopy (HRSTEM) images show low defect density, smooth Fe3O4 thin films. Oxidation at 400 °C resulted in an undesirable second phase in between the TiN and the un-oxidized Fe, but changes in total gas pressure did not lead to a second phase. The crystal structure of this second phase is similar to Fe2TiO4 (ulvöspinel) from HRSTEM and STEM electron energy loss spectroscopy. Fe3O4 thin films grown at 160 °C follow a power law growth model with an exponent of 0.23±0.03.

scholarly journals Synthesis of nanosized vanadium(v) oxide clusters below 10 nm

2019 ◽  
Vol 21 (37) ◽  
pp. 21104-21108 ◽  
Author(s):  
Maximilian Lasserus ◽  
Daniel Knez ◽  
Florian Lackner ◽  
Martin Schnedlitz ◽  
Roman Messner ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy Loss Spectroscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Helium Droplets ◽  
Transmission Electron ◽  
Mean Diameter ◽  
Scanning Transmission ◽  
Electron Energy Loss

Vanadium oxide clusters with a mean diameter below 10 nm are created in helium droplets, and after deposition, studied by Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and UV-vis absorption spectroscopy.

Obtaining the structure factors for an epitaxial film using Cu X-ray radiation

2013 ◽  
Vol 46 (6) ◽  
pp. 1749-1754 ◽  
Author(s):  
P. Wadley ◽  
A. Crespi ◽  
J. Gázquez ◽  
M.A. Roldán ◽  
P. García ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Structure Factor ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Factors ◽  
Scanning Transmission

Determining atomic positions in thin films by X-ray diffraction is, at present, a task reserved for synchrotron facilities. Here an experimental method is presented which enables the determination of the structure factor amplitudes of thin films using laboratory-based equipment (Cu Kα radiation). This method was tested using an epitaxial 130 nm film of CuMnAs grown on top of a GaAs substrate, which unlike the orthorhombic bulk phase forms a crystal structure with tetragonal symmetry. From the set of structure factor moduli obtained by applying this method, the solution and refinement of the crystal structure of the film has been possible. The results are supported by consistent high-resolution scanning transmission electron microscopy and stoichiometry analyses.

Analysis of AlxGa1-xN nanowires through simulated methods of scanning transmission electron microscopy and electron energy-loss spectroscopy

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
R. Kumar ◽  
P.J. Phillips ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

AlxGa1-xN nanowires have promising applications in ultraviolet light emitting diodes (LEDs). However, these nanowires are not typical p-n junction semiconductors, but rather rely on varying concentrations of Al versus Ga to produce electron hole pairs. More information on the atomic structure is needed to better understand the properties of these nanowires. In this study, AlxGa1-xN nanowires were imaged using scanning transmission electron microscopy (STEM) and compared to computer simulated STEM images to obtain physical information on the nanowires. Electron energy-loss spectroscopy (EELS) and FEFF9 computer simulations were also performed to better understand the structural and chemical properties of the nanowires. Results from these simulations showed that changes in the chemical ordering of the nanowires were responsible for changes in intensity and resolution in the images. These intensity and resolution trends were not a result of interface effects. This will help to further characterize nanowires in the future.

Arrangements of Fe-Centered Zn12 Icosahedra in Fe-Zn Intermetallic Compounds Determined by Ultra-High Resolution Scanning Transmission Electron Microscopy

2015 ◽  
Vol 1760 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Akira Yasuhara ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Single Crystal ◽  
Scanning Transmission Electron Microscopy ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Deformation Properties ◽  
Scanning Transmission

ABSTRACTThe crystal structure of the δ1p phase in the Fe-Zn system has been refined by single-crystal synchrotron X-ray diffraction combined with ultra-high resolution scanning transmission electron microscopy. The crystal structure can be described to build up with Fe-centered Zn12 icosahedra. The deformation properties obtained by single-crystal micropillar compression tests of the δ1p phase is discussed in terms of the arrangement of the Fe-centered Zn12 icosahedra in contrast with the ζ phase in the Fe-Zn system.

Redistribution Effects for OMVPE InP/GaAs

1988 ◽  
Vol 144 ◽  
Author(s):  
OH Tae-IL ◽  
Wallace B. Leigh
Keyword(s):  
Electron Diffraction ◽  
Cross Sections ◽  
Scanning Transmission Electron Microscopy ◽  
Field Investigation ◽  
Second Phase ◽  
X Ray ◽  
Substrate Side ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Scanning Transmission

ABSTRACTWe have analyzed the redistribution parameters for InP grown by organometallic vapor phase epitaxy (OMVPE) on GaAs substrates. The layers, grown using (trimethyl Indium) TMIn at atmospheric pressure, have been characterized for epitaxial quality using photoluminescence, energy dispersed x-ray analysis, and optical microscopy. In order to better understand the effects of inter-diffusion and inter-mixing for the GaAs into the InP epitaxial layer, the layer-substrate interface was first probed by growing consecutive samples of InP for increasingly longer growth times, and thus characterizing the layers as one moves away from the interface. For more detailed analysis, cross-sections of the InP/GaAs interface were prepared for scanning transmission electron microscopy (STEM). Energy dispersed x-ray analysis has shown that all elements In, Ga, As, and P, are present on the epitaxial side of the interface, while only Ga and As are present on the substrate side. A combination of electron diffraction and luminescence measurements show the epitaxy is at least 80% InP at the interface and essentially 100% InP at a distance of 6000Å into the epilayer. Electron diffraction and bright field investigation at the interface show the existence of a second phase, existing in a mostly InP matrix. The effects of redistribution in heteroepitaxial InP/GaAs will be discussed.

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