scholarly journals Strain relaxation in InGaN/GaN micro-pillars evidenced by high resolution cathodoluminescence hyperspectral imaging

2012 ◽  
Vol 112 (1) ◽  
pp. 013107 ◽  
Author(s):  
E. Y. Xie ◽  
Z. Z. Chen ◽  
P. R. Edwards ◽  
Z. Gong ◽  
N. Y. Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Hyperspectral Imaging ◽  
Strain Relaxation ◽  
Micro Pillars

COMBINED HRLEED AND STM INVESTIGATIONS ON THE INITIAL STAGES OF Cu HETEROEPITAXY Ru(0001)

1997 ◽  
Vol 04 (06) ◽  
pp. 1167-1171 ◽  
Author(s):  
CH. AMMER ◽  
K. MEINEL ◽  
H. WOLTER ◽  
A. BECKMANN ◽  
H. NEDDERMEYER
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Strain Relaxation ◽  
Local Scale ◽  
Low Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Layer Structures ◽  
Low Energy Electron

Recent scanning tunneling microscopy (STM) observations revealed different layer structures in the heteroepitaxial Cu/Ru(0001) system with increasing film thickness attributed to various stages of strain relaxation. High-resolution low-energy electron diffraction (HRLEED) analysis permits one to derive more exactly both lattice periodicities and lattice rotations. Furthermore, the representative character of local STM results can be proved. However, STM measurements are needed to identify and to assign the satellite spots to coexistent different superstructures which are superposed incoherently in the diffraction pattern. Generally, the integral LEED results confirm the crystallographic data obtained by STM in a local scale.

scholarly journals High-resolution grain size distribution of sediment core with hyperspectral imaging

2019 ◽  
Vol 393-394 ◽  
pp. 105536 ◽  
Author(s):  
Kévin Jacq ◽  
Charline Giguet-Covex ◽  
Pierre Sabatier ◽  
Yves Perrette ◽  
Bernard Fanget ◽  
...  
Keyword(s):  
Grain Size ◽  
High Resolution ◽  
Size Distribution ◽  
Hyperspectral Imaging ◽  
Grain Size Distribution ◽  
Sediment Core

Strain Relaxation in GaN/AlN Films Grown on Vicinal and On-Axis SiC Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 1513-1516
Author(s):  
J. Bai ◽  
X. Huang ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
B. Wagner ◽  
...  
Keyword(s):  
High Resolution ◽  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Crystalline Quality ◽  
Misfit Dislocations ◽  
Vicinal Surface ◽  
Burgers Vector ◽  
Surface Steps ◽  
Transmission Electron ◽  
Initial Stage

Strain relaxation in the GaN/AlN/6H-SiC epitaxial system grown by vicinal surface epitaxy (VSE) is investigated and compared with that in on-axis epitaxy. High resolution x-ray diffraction (HRXRD) measurements show that GaN films grown by VSE have improved crystalline quality. High resolution transmission electron microscope (HRTEM) studies reveal that there are two types of misfit dislocations (MDs) at AlN/6H-SiC interfaces: 60˚ complete dislocations along <1120 > directions with Burgers vector 1/3<1120 > and 60˚ Shockley partials along <10 10 > directions with Burgers vector 1/3<10 10 >. The latter are usually geometrical partial misfit dislocations (GPMDs) that are dominant in VSE to accommodate the lattice mismatch and stacking sequence mismatch simultaneously. In VSE, it is the high-density GPMDs formed at the vicinal surface steps that facilitate rapid strain relaxation at the initial stage of deposition and hence lead to superior crystalline quality of the subsequently grown GaN films.

Hyperspectral drill-core imaging for ore characterization

2020 ◽  
Author(s):  
Laura Tusa ◽  
Mahdi Khodadadzadeh ◽  
Margret Fuchs ◽  
Richard Gloaguen ◽  
Jens Gutzmer
Keyword(s):  
Machine Learning ◽  
Remote Sensing ◽  
High Resolution ◽  
Hyperspectral Imaging ◽  
Mineral Exploration ◽  
Electromagnetic Spectrum ◽  
Drill Core ◽  
Ore Characterization ◽  
Ore Types ◽  
Drill Cores

&lt;p&gt;Mineral exploration campaigns represent an essential step in the discovery and evaluation of ore deposits required to fulfil the global demand for raw materials. Thousands of meters of drill-cores are extracted in order to characterize a specific exploration target. Hyperspectral imaging is recently being explored in the mining industry as a tool to complement traditional logging techniques and to provide a rapid and non-invasive analytical method for mineralogical characterization. The method relies on the fact that minerals have different spectral responses in specific portions of the electromagnetic spectrum. Sensors covering the visible to near-infrared (VNIR) and short-wave infrared (SWIR) are commonly used to identify and estimate the relative abundance of minerals such as phyllosilicates, amphiboles, carbonates, iron oxides and hydroxides as well as sulphates (Clark, 1999). The distribution of these mineral phases can frequently be used as a proxy for the distribution of ore minerals such as sulphides. Typical core imaging systems can acquire hyperspectral data from a whole drill-core tray in a matter of seconds. Available sensors record data in several hundreds of contiguous spectral bands at spatial resolutions around 1 mm/pixel.&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;In this work, we apply a local high-resolution mineralogical analysis, such as SEM-MLA&amp;#160;(Kern&amp;#160;et al., 2018), for a precise and exhaustive mineral mapping of some selected small samples. We then upscale these mineralogical data acquired from thin sections to drill-core scale by integrating hyperspectral imaging and machine learning techniques. Our proposed method is composed of two main steps. In the first step, after initially co-registering the hyperspectral and high-resolution mineralogical data and making a training set, a machine learning model is trained. In the second step, we apply the learned model to obtain mineral abundance and association maps over entire drill-cores.&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;The mapping is further used for the calculation of other mineralogical parameters essential to exploration and further mining stages such as modal mineralogy, mineral association, alteration indices, metal grade estimates and hardness. The proposed methodological framework is illustrated on samples collected from a porphyry type deposit, but the procedure is&amp;#160;easily adaptable to other ore types. Therefore, this approach can be integrated in the standard core-logging routine, complementing the on-site geologists and can serve as background for the geometallurgical analysis of numerous ore types. &amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;Clark, R. N., 1999,&amp;#160;&amp;#8220;Spectroscopy&amp;#160;of rocks and minerals, and principles of spectroscopy,&amp;#8221; in&amp;#160;Remote sensing for the earth sciences: Manual of remote sensing, vol. 3, John Wiley &amp; Sons, Inc, pp. 3&amp;#8211;58.&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;Gandhi, S. M. and Sarkar, B. C., 2016,&amp;#160;&amp;#8220;Drilling,&amp;#8221;&amp;#160;in&amp;#160;Essentials of Mineral Exploration and Evaluation, pp. 199&amp;#8211;234.&lt;/p&gt;&lt;p&gt;&amp;#8203;&amp;#8203;Kern, M., Mo&amp;#776;ckel, R., Krause, J., Teichmann, J., Gutzmer, J., 2018. Calculating the deportment of a fine-grained and compositionally complex Sn skarn with a modified approach for automated mineralogy. Miner. Eng. 116, 213&amp;#8211;225.&lt;/p&gt;

Anisotropic Structural and Electronic Properties of InGaAs/GaAs Heterojunctions

1994 ◽  
Vol 340 ◽  
Author(s):  
R.S. Goldman ◽  
K. Rammohan ◽  
A. Raisanen ◽  
M. Goorsky ◽  
L.J. Brillson ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Electronic Properties ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Polarization Anisotropy ◽  
X Ray ◽  
Bulk Strain ◽  
Gaas Substrates ◽  
Structural And Electronic Properties

ABSTRACTWe have investigated the structural and electronic properties of partially strain-relaxed InxGal-xAs/GaAs heterojunctions, grown by molecular beam epitaxy (MBE) on both misoriented and nominally flat (001) GaAs substrates. Mobility measurements using Hall bars aligned along the [110] and [110] in-plane directions reveal an asymmetry in bulk InGaAs electron mobility. This asymmetry is correlated with an anisotropic bulk strain relaxation and interfacial misfit dislocation density, determined from high-resolution x-ray rocking curves (XRC), as well as a polarization anisotropy in cathodoluminescence (CL).

Model-based Skin Pigment Cartography by High-Resolution Hyperspectral Imaging

2017 ◽  
Vol 2017 (8) ◽  
pp. 108-114
Author(s):  
Pierre Seroul ◽  
Mathieu Hébert ◽  
Marie Cherel ◽  
Romain Vernet ◽  
Raphael Clerc ◽  
...  
Keyword(s):  
High Resolution ◽  
Hyperspectral Imaging ◽  
Model Based ◽  
Skin Pigment
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