Raman scattering study of Si nanoclusters formed in Si through a double Au implantation

2011 ◽  
Vol 1354 ◽  
Author(s):  
Gayatri Sahu ◽  
D.P. Mahapatra
Keyword(s):  
Raman Scattering ◽  
Annealing Time ◽  
High Energy ◽  
Low Energy ◽  
Excitation Wavelength ◽  
Narrow Size Distribution ◽  
Phonon Confinement ◽  
Scattering Study ◽  
Fluence Range ◽  
Confinement Model

ABSTRACTA sequential two step 32 keV Au implantation and 1.5 MeV Au irradiation technique has been used to synthesize Si nanoclusters (NCs) in Si. The low energy amorphising implantation has been carried out over a fluence range of (1 – 100) × 1015 cm−2 while the high energy recrystallizing irradiation fluence was fixed at 1 × 1015 cm−2. Samples were further annealed in air at temperatures between 500° to 950° C for a fixed annealing time of 1 hr and were characterized using Raman scattering at an excitation wavelength of 514.5 nm. Results on as-implanted and irradiated samples indicate formation of strained NCs in the top amorphised layer. Annealing around 500°C has been found to result in strain relief after which the data could be well explained using a phonon confinement model with an extremely narrow size distribution.

Raman scattering crystalline assessment of polycrystalline Cu2ZnSnS4 thin films for sustainable photovoltaic technologies: Phonon confinement model

2014 ◽  
Vol 70 ◽  
pp. 272-280 ◽  
Author(s):  
M. Dimitrievska ◽  
A. Fairbrother ◽  
A. Pérez-Rodríguez ◽  
E. Saucedo ◽  
V. Izquierdo-Roca
Keyword(s):  
Thin Films ◽  
Raman Scattering ◽  
Phonon Confinement ◽  
Photovoltaic Technologies ◽  
Confinement Model

EVIDENCE FOR JAHN-TELLER COUPLING AND FANO RESONANCE OF LOWER Hg MODES IN K3C60 AND Rb3C60 FILMS FROM RAMAN SCATTERING

1992 ◽  
Vol 06 (23n24) ◽  
pp. 4019-4024 ◽  
Author(s):  
V.N. Denisov ◽  
A.A. Zakhidov ◽  
R. Danieli ◽  
G. Ruani ◽  
R. Zamboni ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Wide Band ◽  
Low Energy ◽  
Excitation Energies ◽  
Strong Electron ◽  
Shape Fitting ◽  
Electron Phonon Coupling ◽  
Jahn Teller ◽  
Scattering Study ◽  
Superconducting Pairing

The Raman scattering study of superconducting thin films of A 3 C 60 (A=K,Rb) carried out upon laser excitations at 1.16 and 2.41 eV have revealed the significant broadening and Fano-lineshapes of several low energy H g intramolecular modes with relative intensities and widths depending on excitation energies. The most interesting feature of the 1.16 eV excited spectrum is the wide asymmetric band at 400 cm −1 which can be assigned by Fano-shape fitting to enormously broadened H g (2) mode red shifted compared to its bare frequency of 408 cm −1. The narrowing of all lower H g modes in insulating A 6 C 60 phase indicates strong electron-phonon coupling of this Jahn-Teller modes in x =3 phase and suggests that this low energy vibrations are contributing to superconducting pairing. However the possibility to interpret the wide band at 400 cm −1 as the maximum of electronic background can not be ruled out yet and is supported by our preliminary observations of its disappearance at low temperature below T c .

Raman Scattering Study of Coalesced Single Walled Carbon Nanotubes

1998 ◽  
Vol 13 (9) ◽  
pp. 2405-2411 ◽  
Author(s):  
S. L. Fang ◽  
A. M. Rao ◽  
P. C. Eklund ◽  
P. Nikolaev ◽  
A. G. Rinzler ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Resonant Scattering ◽  
Radial Breathing Mode ◽  
Excitation Wavelength ◽  
Scattering Intensity ◽  
High Temperature Heat Treatment ◽  
Treated Sample ◽  
Scattering Study ◽  
Walled Carbon Nanotubes ◽  
Temperature Heat Treatment

High temperature heat treatment of single wall carbon nanotube bundles in flowing H2 was used to produce a significant fraction (∼40%) of diameter-doubled, or coalesced tubes with a mean diameter corresponding to that of ∼(20, 20) tubes. At three laser excitation wavelengths (514.5, 647, and 1064 nm), a reduction in the Raman scattering intensity of the strong radial and tangential modes was observed in the H2-treated sample, consistent with the reduced fraction of tubes in the sample after coalescence. However, using 488 nm excitation, little or no change is observed in the Raman spectrum after the H2 treatment, suggesting that this excitation wavelength couples only to chiral symmetry tubes. Using the 647 nm excitation, the effect of H2 treatment on the tangential band is quite unique, and a significant change in the shape of the tangential band was observed. Our lineshape analysis, and other results reported in this issue, suggest that this unique change of shape is due to lost scattering intensity from metallic tubes partially compensated by tangential mode scattering from the coalesced tubes. The normally prominent radial breathing mode band, which would be expected at ∼90 cm−1 for ∼(20, 20) tubes was not observed, indicating that these larger diameter tubes do not exhibit strong resonant scattering, at least at any of the wavelengths used in this study.

scholarly journals Electronic Raman-scattering study of low-energy excitations in single and doubleCuO2-layer Tl-Ba-(Ca)-Cu-O superconductors

1997 ◽  
Vol 56 (18) ◽  
pp. R11427-R11430 ◽  
Author(s):  
Moonsoo Kang ◽  
G. Blumberg ◽  
M. V. Klein ◽  
N. N. Kolesnikov
Keyword(s):  
Raman Scattering ◽  
Low Energy ◽  
Electronic Raman Scattering ◽  
Scattering Study

Micro-Raman Scattering Properties of Highly Oriented AlN Films

1998 ◽  
Vol 12 (19) ◽  
pp. 1963-1974 ◽  
Author(s):  
Ming S. Liu ◽  
K. W. Nugent ◽  
S. Prawer ◽  
L. A. Bursill ◽  
J. L. Peng ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Raman Scattering ◽  
Film Plane ◽  
Phonon Confinement ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Transmission Electron ◽  
Scattering Geometry ◽  
Confinement Model

Micro-Raman scattering by highly oriented crystalline aluminum nitride has been measured. Phonon modes in AlN were identified in different scattering geometry configurations and scattering polarizations. The phonon modes revealed that aluminum nitride films are highly oriented with the wurtzite c-axis direction normal to the film plane. The Raman scattering modes are broadened and shifted due to grain boundaries and other defects in the films. The defect scattering was analysed using the phonon confinement model. These results were compared with results obtained from X-ray diffraction powder patterns and high-resolution transmission electron microscopy.

Size-effect Stabilization of the Low-T Ferroelectric Phase in Nanocrystalline WO3

1994 ◽  
Vol 332 ◽  
Author(s):  
Xiang-Xin Bi ◽  
W. T. Lee ◽  
Kai-An Wang ◽  
D. F. Collins ◽  
S. Bandow ◽  
...  
Keyword(s):  
Particle Size ◽  
Raman Scattering ◽  
Size Effect ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
Narrow Size Distribution ◽  
Experimental Conditions ◽  
Scattering Study

ABSTRACTUsing a CO2 laser to drive the pyrolysis of W(CO)6 and O2, we have synthesized nanocrystalline WO3-x particles. These nanopowders are found to exhibit a narrow size distribution with an average particle size produced in the range 5 to 10 nm, depending on the experimental conditions. Typical production rates are ∼ 2 g/h. Results from a Raman scattering study on WO3 nanopowder samples annealed in O2 indicate that a smaller particle size appears to stabilize the low-T ferroelectric phase ( < -40 °C) at room temperature.

Sign in / Sign up

Export Citation Format

Share Document