Phonon Confinement in SiC Nanocrystals: Comparison of the Size Determination Using Transmission Electron Microscopy and Raman Spectroscopy

Silicon carbide fibers of different generation/processing routes (NLM-Nicalon and Tyranno SA3) were thermally treated to trigger the growth of nanocrystals, which were analyzed using Raman spectroscopy and transmission electron microscopy (TEM). The nanocrystals were also aged in molten sodium nitrate to investigate their reactivity. The spatial correlation model has been used to model the Raman spectra and extract accurate and statistical information on the nanocrystallites' structure and dimension. For the NLM fibers, an average size of 2.5 to 7.0 nm was calculated, which was in good agreement with TEM observations. For the Tyranno SA3 fiber, despite the heavily faulted stacking sequence, the Raman peaks remained sharp, indicating that the crystallite dimension calculated from the Raman spectra is only dependent on the actual size of the nanocrystals and is not affected by the sequence of the stacking faults.

Download Full-text

Raman Spectroscopy Analysis of Nitrogen Ion Implantation in Silicon and Correlation with Transmission Electron Microscopy

MRS Proceedings ◽

10.1557/proc-279-177 ◽

1992 ◽

Vol 279 ◽

Author(s):

A. PéRez-Rodríguez ◽

A. Romano-Rodríguez ◽

J. R. Morante ◽

J. Esteve ◽

J. Montserrat

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Raman Spectroscopy ◽

Raman Spectra ◽

Annealing Treatment ◽

Structural Features ◽

Spectroscopy Analysis ◽

Subsurface Region ◽

Transmission Electron ◽

Nitrogen Ion

ABSTRACTIn this work Si samples implanted with nitrogen (N+ or N2+) at a dose of 1017 cm−2 are characterized by Raman spectroscopy and cross section transmission electron microscopy (XTEM). The correlation between the Raman spectra obtained with different excitation wavelengths and XTEM observations allows to determine the structural features related to the layers contributing to the total spectra. The evolution of these features with the annealing treatments (up to 1150°C) is studied. The results obtained show, after the annealing treatment at the highest temperature, the presence of silicon nitride precipitates in the silicon subsurface region, and the formation of a nitrogen rich polycrystalline Si layer with Si3N4 grains. The Raman spectra from the subsurface region show a remaining shift of -0.15 cm−1 when compared to the spectra from unimplanted Si. This shift, together with the similar shape of both Raman lines, suggests the presence in this region of an average tensile stress of 37.5 MPa.

Download Full-text

Characterization of Polysilicon Films by Raman Spectroscopy and Transmission Electron Microscopy: a Comparative Study

MRS Proceedings ◽

10.1557/proc-324-255 ◽

1993 ◽

Vol 324 ◽

Cited By ~ 6

Author(s):

David R. Tallant ◽

Thomas J. Headley ◽

John W. Medernach ◽

Franz Geyling

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Raman Spectroscopy ◽

Raman Spectra ◽

Cross Section ◽

Nanometer Scale ◽

Sampling Depth ◽

Transmission Electron ◽

Polysilicon Films

AbstractSamples of chemically-vapor-deposited sub-micrometer-thick films of polysilicon were analyzed by transmission electron microscopy (TEM) in cross-section and by Raman spectroscopy with illumination at their surface. TEM and Raman spectroscopy both find varying amounts of polycrystalline and amorphous silicon in the wafers. Raman spectra obtained using blue, green and red excitation wavelengths to vary the Raman sampling depth are compared with TEM crosssections of these films. Some films have Raman spectra with a band near 497 cm−1, corresponding to numerous nanometer-scale faulted regions in the TEM micrographs.

Download Full-text

Structure of Oxides Grown on Zr-20Nb Alloy

MRS Proceedings ◽

10.1557/proc-357-219 ◽

1994 ◽

Vol 357 ◽

Cited By ~ 3

Author(s):

O.T. Woo ◽

D.J. Lockwood ◽

Y.P. Lin ◽

V.F. Urbanic

Keyword(s):

Crystal Structure ◽

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Raman Spectroscopy ◽

Raman Spectra ◽

High Symmetry ◽

X Ray Diffraction ◽

Short Term ◽

X Ray ◽

Transmission Electron

AbstractOxides grown on Zr-20Nb were characterized by Raman Spectroscopy (RS), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). These oxides were steamformed at 400°C, water-formed at 360 °C and at 300 °C, and air-grown at 400°C. For the oxides grown after relatively short exposures at 360°C and at 400°C, Raman spectra revealed broad peaks at 260 and 660 cm− indicating a crystal structure with high symmetry. Comparison with reference Raman spectra of cubic (c), tetragonal (t), and monoclinic (m) ZrO2 suggested that the oxide was predominantly nearly-cubic (tetragonal with c/a ratio ≈ 1), with minor amounts of moxide. The tetragonality is found to be consistent with TEM analyses and XRD results which showed the presence of a doublet near 2θ ° 74°. The crystal structure in the short-term exposed oxides is interpreted in terms of a tetragonal distortion arising from the displacement of oxygen atoms within the cubic ZrO2 crystal structure. For oxides grown after longer periods of exposure at 300°C and at 400°C, RS and XRD indicate increased amounts of m-oxide.

Download Full-text

CdS x Se 1− x quantum dots as colouring agents of Art Nouveau and contemporary stained glass: a combined transmission electron microscopy and Raman study

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2016.0045 ◽

2016 ◽

Vol 374 (2082) ◽

pp. 20160045 ◽

Cited By ~ 6

Author(s):

C. Fornacelli ◽

Ph. Sciau ◽

Ph. Colomban

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Raman Spectroscopy ◽

Elemental Composition ◽

Raman Band ◽

Peak Position ◽

Stained Glass ◽

Transmission Electron ◽

Means Of Transmission ◽

Average Size

The use of cadmium chalchogenide nanoprecipitates to obtain brightly coloured glasses enormously expanded by the beginning of the twentieth century, when the production of cadmium-based pigments was already well established. Six historical stained glass pieces produced between the late 1920s and modern days have been investigated in order to delineate the average size and the elemental composition of the nanocrystals. As non-invasive conditions are now mandatory when considering objects belonging to cultural heritage, Raman spectroscopy is used to measure the (average) elemental composition of the nanoparticles. Zinc substitution is also detected by the shifting of the Raman peak position. Moreover, a tentative evaluation of size distribution and crystallinity of the nanoparticles has been performed considering those parameters that are mainly influenced by the disorder of the system, such as Raman band width, surface phonons and the ratio between second and first order band intensities. A confirmation of the above-mentioned conclusion is searched by means of transmission electron microscopy (TEM) and local elemental analysis. Raman investigations allowed identifying a different and more pronounced disorder characterizing the oldest glasses, also verified by TEM observations, suggesting a different manufacture. This article is part of the themed issue ‘Raman spectroscopy in art and archaeology’.

Download Full-text