scholarly journals Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

10.3791/53026 ◽  
2015 ◽  
Author(s):  
İlker Doğan ◽  
Mauritius C. M. van de Sanden
Keyword(s):  
Raman Spectroscopy ◽  
Size Distribution ◽  
Nanocrystal Size ◽  
Phonon Confinement ◽  
Confinement Model

scholarly journals Direct characterization of nanocrystal size distribution using Raman spectroscopy

2013 ◽  
Vol 114 (13) ◽  
pp. 134310 ◽  
Author(s):  
İlker Doğan ◽  
Mauritius C. M. van de Sanden
Keyword(s):  
Raman Spectroscopy ◽  
Size Distribution ◽  
Nanocrystal Size

Raman Spectroscopy of Ge Nanocrystals Grown by Self-Organization Processes

1996 ◽  
Vol 452 ◽  
Author(s):  
A. Stella ◽  
C. E. Bottani ◽  
P. Cheyssac ◽  
R. Kofman ◽  
P. Milani ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Size Dependence ◽  
Self Organization ◽  
Phonon Confinement ◽  
Amorphous Substrate ◽  
Crystalline Nature ◽  
Size Dispersion ◽  
Ge Nanocrystals ◽  
Confinement Model

AbstractWe report Raman spectroscopy measurements on Ge nanocrystals with average radii ranging from about 65 Å down to 10 Å (with a size dispersion lower than 20 %).Ge has been deposited by UHV evaporation on an amorphous substrate, kept at such a temperature as to produce the Ge nanodroplets nucleation in the liquid phase.A nanocrystalline size dependence of the Raman spectra has been observed and explained in the framework of a phonon confinement model. We have observed the softening of the TO Raman peak predicted by the theory when the dimensions of the particles are decreased. Moreover the observed inhomogeneous broadening of the Raman lines has been correlated with the size distribution of the particles in the samples.Our results provide a characterization of Ge nanoparticles exhibiting a good crystalline nature, down to about 10 Å, and in conditions of substantial absence of perturbations of the environment.

Modified phonon confinement model for Raman spectroscopy of nanostructured materials

2010 ◽  
Vol 82 (11) ◽  
Author(s):  
K. Roodenko ◽  
I. A. Goldthorpe ◽  
P. C. McIntyre ◽  
Y. J. Chabal
Keyword(s):  
Raman Spectroscopy ◽  
Nanostructured Materials ◽  
Phonon Confinement ◽  
Confinement Model

Formation and characterization of germanium nanoparticles

2000 ◽  
Vol 15 (11) ◽  
pp. 2400-2407 ◽  
Author(s):  
N. J. Welham
Keyword(s):  
Raman Spectroscopy ◽  
Crystallite Size ◽  
Magnesium Oxide ◽  
Phonon Confinement ◽  
X Ray Diffraction ◽  
Acid Leach ◽  
Crystallite Sizes ◽  
Crystal Core ◽  
Individual Particles

Elemental germanium was mechanically milled with magnesium oxide with the intention of forming disperse nanoparticulate germanium in a soluble matrix. The crystallite size was determined by x-ray diffraction (XRD) and Raman spectroscopy using a phonon confinement model. The crystallite size was found to decrease exponentially with milling time; however, the size determined by XRD was typically five to ten times greater than that by Raman. This was attributed to the presence of two separate crystallite sizes, which were averaged when using the Scherrer equation for the XRD data. Sonication of the powder resulted in the breakup of >20 μm aggregates into individual particles of approximately 40 nm. These particles are thought to compose a single crystal core with a crystallite size of approximately 28 nm surrounded by a layer of smaller crystallites (approximately 5 nm), which showed quantization during Raman spectroscopy. Separation of the germanium from the magnesium oxide was readily achieved using a simple acid leach, although some oxidation of germanium was evident when using an aqueous leach.

scholarly journals Characterization of anatase TiO2 nanopowder by variable-temperature Raman spectroscopy

2009 ◽  
Vol 41 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Maja Scepanovic ◽  
M. Grujic-Brojcin ◽  
Z.D. Dohcevic-Mitrovic ◽  
Z.V. Popovic
Keyword(s):  
Raman Spectroscopy ◽  
Grain Size ◽  
Variable Temperature ◽  
Anatase Phase ◽  
Great Influence ◽  
Tio2 Powder ◽  
Phonon Confinement ◽  
Anti Stokes ◽  
Nanosized Tio2

Raman spectroscopy has been used for characterization of commercial nanosized TiO2 powder with declared grain size of 5 nm. The Raman spectra measured in Stokes and anti-Stokes regime confirm the anatase phase of TiO2 powder in temperature range 25-1173K. It is shown that phonon-confinement (due to small grain size) and nonstoichiometry (caused by laser irradiation in vacuum) have a great influence on blueshift and broadening of the main Eg Raman mode at low temperatures, while the influence of the strong anharmonic effect becomes dominant at higher temperatures. The phonon confinement effect decreases due to the crystallite growth at temperatures above 673K.

scholarly journals Behavior of porous silicon crystallite size analized by Raman spectroscopy and phonon confinement model

2015 ◽  
Vol 34 (2) ◽  
pp. 75
Author(s):  
Miguel Angelo Do Amaral Junior ◽  
Neidenêi Gomes Ferreira ◽  
Antonio Fernando Beloto ◽  
Maurício Ribeiro Baldan
Keyword(s):  
Raman Spectroscopy ◽  
Porous Silicon ◽  
Crystallite Size ◽  
Phonon Confinement ◽  
Confinement Model

Characterization of Pancreas at Diabetic Patients in CT images using Texture Analysis

2017 ◽  
Vol 7 (7) ◽  
pp. 8
Author(s):  
Mona E. Elbashier ◽  
Suhaib Alameen ◽  
Caroline Edward Ayad ◽  
Mohamed E. M. Gar-Elnabi
Keyword(s):  
Size Distribution ◽  
Texture Analysis ◽  
Classification Accuracy ◽  
Ct Images ◽  
Diabetic Patients ◽  
Gray Level ◽  
Grey Level ◽  
Run Length ◽  
Interactive Data

This study concern to characterize the pancreas areato head, body and tail using Gray Level Run Length Matrix (GLRLM) and extract classification features from CT images. The GLRLM techniques included eleven’s features. To find the gray level distribution in CT images it complements the GLRLM features extracted from CT images with runs of gray level in pixels and estimate the size distribution of thesubpatterns. analyzing the image with Interactive Data Language IDL software to measure the grey level distribution of images. The results show that the Gray Level Run Length Matrix and  features give classification accuracy of pancreashead 89.2%, body 93.6 and the tail classification accuracy 93.5%. The overall classification accuracy of pancreas area 92.0%.These relationships are stored in a Texture Dictionary that can be later used to automatically annotate new CT images with the appropriate pancreas area names.

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