Spectral characteristics of (111) silicon with Raman selections under different states of stress

Qiu, Wei; Ma, Lulu; Xing, Huadan; Cheng, Cui-Li; Huang, Gan-Yun

doi:10.1063/1.4992106

Cited by 13 publications

(11 citation statements)

References 27 publications

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“…To analyze RS from Si(111), we consider coordinate system with the axes x 1 ‐(1

\overset{1}{true}

0), y 1 ‐(11

\overset{2}{true}

), z 1 ‐(111), in which Raman tensors (2) are given by

{R^{x_{1}}}_{αβ} = ((), \begin{array}{c} 0 & \frac{1}{\sqrt{3}} \\ \frac{1}{\sqrt{3}} & - \frac{2}{3} \end{array}), {R^{y_{1}}}_{αβ} = ((), \begin{array}{c} 0 & - \frac{1}{\sqrt{3}} \\ - \frac{1}{\sqrt{3}} & - \frac{2}{3} \end{array}), {R^{z_{1}}}_{αβ} = ((), \begin{array}{c} - 1 & 0 \\ 0 & \frac{1}{3} \end{array}) .

…”

Section: Resultsmentioning

confidence: 99%

Circularly polarized Raman scattering in silicon

Talochkin

2019

J Raman Spectroscopy

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The two-dimensional layered materials such as graphene and transition metal dichalcogenides reveal the unique structure of the electron-hole spectrum that generates discrete degrees of freedom related to the electron spin and the valley pseudospin. Optical phonons with the angular momentum may induce the transitions between the quantum levels in this system. Therefore, the investigation of these phonons is of particular importance now. One of the most popular methods for the determination of the angular momentum of optical phonons is circularly polarized Raman spectroscopy, common features of which were not entirely discovered so far due to a restricted set of studied materials. Here, we use this method to examine optical phonons in Si as an example of a highsymmetry model crystal. The decomposition of scattered light into the circularly polarized components with the subsequent angle-resolved analysis is employed. This allows us to find that Raman scattering by longitudinal optical phonons occurs with conservation of the photon helicity in accordance to the angular momentum conservation law, since the longitudinal optical phonon angular momentum is zero. In contrast, transverse optical phonon reverses photon helicity, meaning that its angular momentum is 2ħ. It is shown that Raman scattering of circularly polarized light is described well taking into account the angular momentum conservation law in addition to the main conclusions of the classical theory developed for the case of linearly polarized light.

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“…To analyze RS from Si(111), we consider coordinate system with the axes x 1 ‐(1

\overset{1}{true}

0), y 1 ‐(11

\overset{2}{true}

), z 1 ‐(111), in which Raman tensors (2) are given by

{R^{x_{1}}}_{αβ} = ((), \begin{array}{c} 0 & \frac{1}{\sqrt{3}} \\ \frac{1}{\sqrt{3}} & - \frac{2}{3} \end{array}), {R^{y_{1}}}_{αβ} = ((), \begin{array}{c} 0 & - \frac{1}{\sqrt{3}} \\ - \frac{1}{\sqrt{3}} & - \frac{2}{3} \end{array}), {R^{z_{1}}}_{αβ} = ((), \begin{array}{c} - 1 & 0 \\ 0 & \frac{1}{3} \end{array}) .

…”

Section: Resultsmentioning

confidence: 99%

Circularly polarized Raman scattering in silicon

Talochkin

2019

J Raman Spectroscopy

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“…It should be noted that the ability to precisely measure the position of a band is much more a function of the wavelength precision of the instrument than of the spectral resolution. We are not trying to resolve two closely spaced bands, but rather to distinguish two samples with slight differences in the position of the same band like examples involving material stress measurements where bond angles change resulting in the Raman band associated with those bonds moving to a slightly different frequency . The limiting factor for this analysis is not going to be the resolution, but rather the precision (reproducibility).…”

Section: Results and Discussionmentioning

confidence: 99%

“…We are not trying to resolve two closely spaced bands, but rather to distinguish two samples with slight differences in the position of the same band like examples involving material stress measurements where bond angles change resulting in the Raman band associated with those bonds moving to a slightly different frequency. 57 The limiting factor for this analysis is not going to be the resolution, but rather the precision (reproducibility). For the Raman instrument we used in this work, the maximum RMS variation in peak position at any single point in the map between the five repeats is only 0.022 cm −1 .…”

Section: Acs Applied Bio Materialsmentioning

confidence: 99%

In Situ Monitoring the Aggregation Dynamics of Amyloid-β Protein Aβ42 in Physiological Media via a Raman-Based Frequency Shift Method

Zhu

Wang

Xie

et al. 2018

ACS Appl. Bio Mater.

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Amyloid-β protein (Aβ) is a major biomarker candidate for the diagnosis of Alzheimer’s disease (AD). It is known that the core segment of Aβ42 tends to aggregate into neurotoxic soluble oligomeric species and finally into fibrillar structures associated with AD; however, much remains to be learned about the conformational changes and dynamic aggregation processes of Aβ protein in solution. Herein we exploit the selectivity of affinity peptides, singled out by biopanning a phage display library, to recognize and capture Aβ42 and its fibers. The sensitivity of surface-enhanced Raman spectroscopy (SERS) to subtle electronic changes of a Raman reporter upon Aβ42 binding, that is, the frequency shift SERS assay, is employed to develop a reliable sensor for both in situ Aβ42 aggregation monitoring and Aβ42 monomers and fibers detection. Atomic force microscope (AFM) imaging is used to investigate the dynamic aggregation processes of Aβ42 on mica and confirms the conclusions of the SERS studies. Finally sensing of Aβ42 and its fibers in fetal bovine serum (FBS) solution is shown to have a limit of detection of ∼10–9 mol/L.

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“…In the early 1970s, for example, the Raman frequency shift was used to investigate the effect of static uniaxial stress on silicon and to detect atmospheric pollutants (e.g., oil smoke and automobile exhaust gas) . The frequency shift is widely used for the measurement of stress in (111) silicon, for example, to investigate residual stress in porous silicon films due to a lattice mismatch between the film and substrates. , …”

mentioning

confidence: 99%

“…34 The frequency shift is widely used for the measurement of stress in (111) silicon, for example, to investigate residual stress in porous silicon films due to a lattice mismatch between the film and substrates. 35,36 In this Minireview, however, we focus specifically on the use of SERS frequency-shift assays for biomolecule and small molecule assaying, first discussing the various mechanisms that induce frequency shifts and second discussing assay fabrication and the incorporation of metallic nanostructures. Third, we highlight the advantages of SERS frequency-shift assays for multiplex protein detection and more recent assays for RNA/ DNA, ions, and small molecules.…”

mentioning

confidence: 99%

Frequency Shift Surface-Enhanced Raman Spectroscopy Sensing: An Ultrasensitive Multiplex Assay for Biomarkers in Human Health

et al. 2021

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The sensitive and selective detection of biomarkers for human health remains one of the grand challenges of the analytical sciences. Compared to established methods (colorimetric, (chemi) luminescent), surface-enhanced Raman spectroscopy (SERS) is an emerging alternative with enormous potential for ultrasensitive biological detection. Indeed even attomolar (10 −18 M) detection limits are possible for SERS due to an orders-ofmagnitude boosting of Raman signals at the surface of metallic nanostructures by surface plasmons. However, challenges remain for SERS assays of large biomolecules, as the largest enhancements require the biomarker to enter a "hot spot" nanogap between metal nanostructures. The frequency-shift SERS method has gained popularity in recent years as an alternative assay that overcomes this drawback. It measures frequency shifts in intense SERS peaks of a Raman reporter during binding events on biomolecules (protein coupling, DNA hybridization, etc.) driven by mechanical transduction, charge transfer, or local electric field effects. As such, it retains the excellent multiplexing capability of SERS, with multiple analytes being identifiable by a spectral fingerprint in a single read-out. Meanwhile, like refractive index surface plasmon resonance methods, frequency-shift SERS measures the shift of an intense signal rather than resolving a peak above noise, easing spectroscopic resolution requirements. SERS frequency-shift assays have proved particularly suitable for sensing large, highly charged biomolecules that alter hydrogen-bonding networks upon specific binding. Herein we discuss the frequency-shift SERS method and promising applications in (multiplex) biomarker sensing as well as extensions to ion and gas sensing and much more.

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Spectral characteristics of (111) silicon with Raman selections under different states of stress

Cited by 13 publications

References 27 publications

Circularly polarized Raman scattering in silicon

Circularly polarized Raman scattering in silicon

In Situ Monitoring the Aggregation Dynamics of Amyloid-β Protein Aβ42 in Physiological Media via a Raman-Based Frequency Shift Method

Frequency Shift Surface-Enhanced Raman Spectroscopy Sensing: An Ultrasensitive Multiplex Assay for Biomarkers in Human Health

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