A Device for Surface-Scanning Micro-Raman Spectroscopy

Lankers, M.; Göttges, D.; Materny, Arnulf; Schaschek, K.; Kiefer, W.

doi:10.1366/0003702924123728

Cited by 25 publications

(9 citation statements)

References 7 publications

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“…In the literature only theoretical treatments of the size-dependent phonon frequency shift are reported. ,, Shiang and co-workers 13 have suggested a theoretical model concerned with the phonon confinement in CdS nanocrystallites that predicts a considerable shift of the LO frequency to lower energies as well as an asymmetrical broadening of the LO band for decreasing crystallite sizes. The applied model is based on the vibrational multimode nature for lattices with finite sizes.…”

Section: Resultsmentioning

confidence: 99%

Sol−Gel Synthesis and Spectroscopic Properties of Thick Nanocrystalline CdSe Films

et al. 1997

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Two novel metal alkoxide-derived routes were developed for the synthesis of nanocrystalline CdSe layers with quantum dot sizes between 1 and 4 nm. The first route, where cadmium ethoxy−acetate is reacted with bis(trimethylsilyl)selenium in the presence of aminopropyltriethoxysilane (AMEO), yields highly concentrated alcoholic 0.5 M sols for direct coatings. The second route allows to grow CdSe clusters by infiltrating the selenium precursor into Cd-enriched organosilicate gel layers. The resulting optically transparent films with thicknesses near 10 μm (obtained in a single-step coating) were characterized by steady-state optical absorption and photoluminescence spectroscopy, high-resolution electron microscopy (HRTEM), X-ray diffraction (XRD), resonance Raman, and time-resolved photoluminescence spectroscopy. The experimental data reveal the presence of nanocrystals exhibiting a tetrahedral shape. The quantum dot films are strongly fluorescing, with a quantum yield near 10%. The decay characteristics of the photoluminescence signal after pulsed excitation is discussed taking into account the splitting of the quantum dot ground state as well as the influence of surface states. Furthermore, a size-dependent shift of the Raman band, attributed to the longitudinal optical phonon of the consolidated CdSe clusters, could be observed. This shift is accompanied by a broadening of the corresponding Raman line width. Both effects, the size-dependent shift as well as the broadening of the Raman line width, indicate that phonon confinement is present for the clusters under consideration.

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Section: Resultsmentioning

confidence: 99%

Sol−Gel Synthesis and Spectroscopic Properties of Thick Nanocrystalline CdSe Films

et al. 1997

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“…15 The micro Raman spectra were recorded using different excitation wavelengths of an argon ion laser (Spectra Physics Model 166) and of a dye laser (Spectra Physics Model 375B). The Raman microscope has been described in detail elsewhere.…”

Section: Methodsmentioning

confidence: 99%

Resonance Raman spectroscopy on strain relaxed CdZnSe/ZnSe quantum wires

Schreder

Materny

Kiefer

et al. 2000

J. Raman Spectrosc.

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Cd0.35Zn0.65Se/ZnSe and Cd0.2Zn0.8Se/ZnSe quantum wells grown by molecular beam epitaxy were patterned by electron beam lithography and wet chemical etching to give quantum wires of widths down to the sub‐100 nm range. The splitting between the ZnSe LO phonon of the barrier layers and the ZnSe‐like LO phonon of the quantum well layer was investigated by applying different excitation wavelengths. For two wire fields with different wire sizes excitation profiles were recorded, which show features belonging to the incoming and outgoing resonance of the LO phonon fundamental vibration and its first overtone. As a result, the LO phonon wavenumber of the wire shows a small shift on changing the excitation wavelength, which is due to changes in the relative intensities of the contributions of the wire center and the wire edges. The wavenumber positions of these two peak contributions are independent of the different resonance conditions at the edge and in the middle of the wire. Copyright © 2000 John Wiley & Sons, Ltd.

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“…In the case of 514.5 nm excitation, a triple monochromator (Dilor X-Y) equipped with an optical multichannel analyzer (OMA) was applied. Laser and Raman scattering were focused by means of a micro-Raman setup described by Lankers et al 11 A double monochromator SPEX model 1404 and a CCD (charge coupled device) system Photometrics model CCD 9000, were used for dispersion and detection of spectra obtained by means of the 647.1 nm line. The rotating-surface-scanning technique reported by Zimmerer and Kiefer was applied in this case.…”

Section: Spectroscopic Measurementsmentioning

confidence: 99%

Vibrational spectroscopic study of tetracalcium phosphate in pure polycrystalline form and as a constituent of a self-setting bone cement

Posset

Löcklin

Thulĺ

et al. 1998

J. Biomed. Mater. Res.

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Polycrystalline tetracalcium phosphate (TTCP), a material of considerable interest for human implantation due to its similarity to hydroxyapatite, was studied by means of Raman and FT-IR spectroscopy. The spectra were interpreted on the basis of group theoretical considerations. In addition, the setting reaction of a calcium phosphate cement (CPC) consisting of an equimolar mixture of TTCP and dicalcium phosphate (DCPA) was investigated by Raman spectroscopy. The band of the totally symmetric phosphate mode v1 of TTCP showed marked factor group splittings. The splitting components arose at coincident wave numbers in the IR and Raman spectra. This observation was in accordance with space group P2(1) (factor group C2(2), Z = 4). The characteristic splitting of v1 allowed the setting reaction of CPC to hydroxyapatite to be followed. According to the Raman spectroscopic results, considerable amounts of TTCP must be present at the sample surface after 24 h of setting in an aqueous environment.

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A Device for Surface-Scanning Micro-Raman Spectroscopy

Cited by 25 publications

References 7 publications

Sol−Gel Synthesis and Spectroscopic Properties of Thick Nanocrystalline CdSe Films

Sol−Gel Synthesis and Spectroscopic Properties of Thick Nanocrystalline CdSe Films

Resonance Raman spectroscopy on strain relaxed CdZnSe/ZnSe quantum wires

Vibrational spectroscopic study of tetracalcium phosphate in pure polycrystalline form and as a constituent of a self-setting bone cement

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