scholarly journals Determining Strain, Chemical Composition, and Thermal Properties of Si/SiGe Nanostructures via Raman Scattering Spectroscopy

2018 ◽  
Author(s):  
Leonid Tsybeskov ◽  
Selina A. Mala ◽  
Xialou Wang ◽  
Jean-Marc Baribeau ◽  
Xiaohua Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Chemical Composition ◽  
Raman Scattering ◽  
Optoelectronic Devices ◽  
Low Frequency ◽  
Spectral Features ◽  
Raman Scattering Spectroscopy ◽  
Inelastic Light Scattering ◽  
Polarized Raman

Studies by Raman spectroscopy of two kinds of Si/SiGenanostructures—quantum dot multilayers and planarsuperlattices—reveal a wide variety of spectral features including first- and second-order Raman scattering, polarized Raman scattering, and low-frequency inelastic light scattering associated with folded acoustic phonons. Here we overview how such features can be employed to semi-quantitatively analyze the strain, chemical composition, and thermal conductivity in these industrially important materials that are widely used for producing electronic and optoelectronic devices.

CdZnSe/Zn(Be)Se Quantum Dot Structures: Size, Chemical Composition and Phonons

2003 ◽  
Vol 799 ◽  
Author(s):  
Y. Gu ◽  
Igor L. Kuskovsky ◽  
J. Fung ◽  
R. Robinson ◽  
I. P. Herman ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Composition ◽  
Quantum Dot ◽  
Raman Scattering ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Optically Active ◽  
Photoluminescence Excitation ◽  
Quantum Size ◽  
Polarized Raman

ABSTRACTThe size and chemical composition of optically active CdZnSe/ZnSe and CdZnSe/Zn0.97Be0.03Se quantum dots (QDs) are determined using photoluminescence, photoluminescence excitation and polarized Raman scattering spectroscopies. We show that the addition of Be into the barrier enhances the Cd composition and the quantum size effect of optically active QDs. Additionally, surface phonons from QDs are observed in CdZnSe/ZnBeSe nanostructures.

Polarized Raman scattering and low frequency infrared study of hydroxyapatite

1977 ◽  
Vol 21 (12) ◽  
pp. v-vi
Author(s):  
Z. Iqbal ◽  
V.P. Tomaselli ◽  
O. Fahrenfeld ◽  
K.D. Möller ◽  
F.A. Ruszala ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Low Frequency ◽  
Infrared Study ◽  
Polarized Raman

scholarly journals Crosslinking Effect on Thermal Conductivity of Electrospun Poly(acrylic acid) Nanofibers

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 858 ◽  
Author(s):  
Yeongcheol Park ◽  
Suyeong Lee ◽  
Sung Soo Ha ◽  
Bernard Alunda ◽  
Do Young Noh ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Acrylic Acid ◽  
Conformational Changes ◽  
Fold Increase ◽  
The Other ◽  
Thermal Treatments ◽  
Polarized Raman Spectroscopy ◽  
Polarized Raman ◽  
Poly Acrylic Acid

The thermal conductivity (k) of poly(acrylic acid) (PAA) nanofibers, which were electrospun at various electrospinning voltages, was measured using suspended microdevices. While the thermal conductivities of the as-spun PAA nanofibers varied depending on the electrospinning voltages, the most pronounced 3.1-fold increase in thermal conductivity in comparison to that of bulk PAA was observed at the electrospinning voltage of 14 kV. On the other hand, a reduction in the thermal conductivity of the nanofibers was observed when the as-spun nanofibers were either thermally annealed at the glass transition temperature of PAA or thermally crosslinked. It is notable that the thermal conductivity of crosslinked PAA nanofibers was comparable to that of crosslinked bulk PAA. Polarized Raman spectroscopy and Fourier transform infrared spectroscopy verified that the k enhancement via electrospinning and the k reduction by the thermal treatments could be attributed to the conformational changes between gauche and trans states, which may be further related to the orientation of molecular chains. In contrast, hydrogen bonds did not contribute significantly to the k enhancement. Additionally, the suppression of k observed for the crosslinked PAA nanofibers might result from the shortening of single molecular chains via crosslinking.

scholarly journals Raman scattering studies of order parameters in liquid crystalline dimers exhibiting the nematic and twist-bend nematic phases

2015 ◽  
Vol 3 (38) ◽  
pp. 10007-10016 ◽  
Author(s):  
Zhaopeng Zhang ◽  
Vitaly P. Panov ◽  
Mamatha Nagaraj ◽  
Richard J. Mandle ◽  
John W. Goodby ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Homologous Series ◽  
Liquid Crystalline ◽  
Orientational Order ◽  
Order Parameters ◽  
Polarized Raman Spectroscopy ◽  
Nematic Phases ◽  
Polarized Raman

The work deduces orientational order parameters in the nematic and twist-bend nematic phases. An homologous series of dimers is studied using Polarized Raman Spectroscopy.

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