Raman scattering in amorphous silicon films

Avakyants, L. P.; Gerasimov, L.L.; Горелик, В. С.; Manja, N.M.; Obraztsova, E. D.; Plotnikov, Yu.I.

doi:10.1016/0022-2860(92)87028-t

Cited by 17 publications

(11 citation statements)

References 13 publications

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“…A deeper insight into the bulky structure of the three different Si nanosheets has been derived by a comparative Raman spectroscopy study enabling a clear-cut discrimination of the nanoscale Si phase as previously deduced for the single-layer silicene. , Figure a shows the Raman spectra of the nanoscale Si samples grown in the three different GT regimes compared to bulk Si(111). The low-GT sample features a broad Raman peak centered at 480 cm –1 consistent with amorphous Si, whereas both multilayer silicene and diamond-like Si exhibit a quite sharp Raman peak at 524 cm –1 (according to ref ) and 521.5 cm –1 , respectively. Hence, increasing the GT leads to a red shift in the Raman peak tending to that of bulk Si(111), which is placed at 520.4 cm –1 .…”

Section: Resultsmentioning

confidence: 86%

Silicon Nanosheets: Crossover between Multilayer Silicene and Diamond-like Growth Regime

Grazianetti¹,

Cinquanta²,

Tao

et al. 2017

ACS Nano

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The structural and electronic properties of nanoscale Si epitaxially grown on Ag(111) can be tuned from a multilayer silicene phase, where the constitutive layers incorporate a mixed sp/sp bonding, to other ordinary Si phases, such as amorphous and diamond-like Si. Based on comparative scanning tunneling microscopy and Raman spectroscopy investigations, a key role in determining the nanoscale Si phase is played by the growth temperature of the epitaxial deposition on Ag(111) substrate and the presence or absence of a single-layer silicene as a seed for the successive growth. Furthermore, when integrated into a field-effect transistor device, multilayer silicene exhibits a characteristic ambipolar charge carrier transport behavior that makes it strikingly different from other conventional Si channels and suggestive of a Dirac-like character of the electronic bands of the crystal. These findings spotlight the interest in multilayer silicene as a different nanoscale Si phase for advanced nanotechnology applications such as ultrascaled nanoelectronics and nanomembranes, as well as for fundamental exploration of quantum properties.

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Section: Resultsmentioning

confidence: 86%

Silicon Nanosheets: Crossover between Multilayer Silicene and Diamond-like Growth Regime

Grazianetti¹,

Cinquanta²,

Tao

et al. 2017

ACS Nano

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“…The Raman spectra of the Si nanomeshes are shown in Figure . The spectra in Figure are evaluated by the observed peak at 520 cm –1 , which is due to the LO phonon mode associated with crystalline Si …”

Section: Resultsmentioning

confidence: 99%

“…This indicates that the nQS disorder in the inert nanomeshes (nQS-grain boundary disorder) exhibits larger Raman activity than the nQS disorder observed in the oxygenated nanomeshes (surface nQS nanovoid disorder). This suggests that the increased nQS-grain boundary disorder is causing an increase in the vibrational activity of the LO phonon mode of within Si that is responsible for the 520 cm –1 peak …”

Section: Resultsmentioning

confidence: 99%

“…The spectra in Figure 6 are evaluated by the observed peak at 520 cm −1 , which is due to the LO phonon mode associated with crystalline Si. 62 The spectra in Figure 6 show that the Raman activity of the nanomesh structures is highly dependent on both the type of nQS disorder within which the nanomeshes are formed and the wavelength of the Raman laser used to acquire the spectra. These spectra reveal that the type of defect present within the nanomesh structures plays a significant role in the Raman activity of the nanomesh and that the Raman activity caused by the subnano disorder is wavelength dependent.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Toward Universal SERS Detection of Disease Signaling Bioanalytes Using 3D Self-Assembled Nonplasmonic near-Quantum-Scale Silicon Probe

Powell¹,

Venkatakrishnan

Tan³

2017

ACS Appl. Mater. Interfaces

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Currently, the quantum-scale surface-enhanced Raman scattering (SERS) properties of Si materials have yet to be discovered for universal biosensing applications. In this study, a potential universal biosensing probe is generated by activating the SERS functionality of Si nanostructures through near quantum-scale (nQS) engineering. We introduce herein 3D nonplasmonic Si nanomesh structure with nQS defects for SERS biosensing applications. Through ionization of a single-crystal defect-free Si wafer, highly defect-rich Si subnano-orbs (sNOs) are fabricated and self-assemble as connective 3D Si nanomesh structures with enhanced SERS biosensing activity. By amending the laser ionization and ion-ion interactions, we observe the controlled synthesis of engineered nQS defects in the form of nQS-grain boundary disorder or surface nQS voids within the interconnected Si sNOs. To our knowledge, it is shown here for the first time that defect-rich Si nanomesh structures exhibit enhanced Raman activity, with the nQS morphological and crystallographic defects acting as the prime SERS contributors without a plasmonic contribution. The SERS biosensing sensitivity with the synthesized defect-rich Si nanomesh structures without an additional plasmonic material was evaluated using of a tripeptide biomarker l-glutathione (GSH); we observe an enhancement factor value of ∼10 for the GSH biomolecules with 10 M sensitivity, a phenomena to our knowledge that has yet to be reported. Additionally, the SERS detection of multiple disease-signaling biomolecules (cysteine, tryptophan, and methionine) is achieved at very low analyte concentration (10 M). These results indicate a potential new dimension to universal SERS biosensing applications with these unique nonplasmonic defect-rich 3D nQS-Si nanostructures.

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“…Si-Si signal was not observed, suggesting that there was not Si segregation. The spectra for pure silicon samples show the characteristic bands of amorphous silicon [20].…”

Section: Resultsmentioning

confidence: 97%

Fullerene-silicon polymerization evidence

Ej¹,

Huck‐Iriart²,

Eb³

et al. 2017

Interdiscip J Chem

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Volume 2(2): 1-4 the chamber. The substrate was polarized at -30 V during the process. Substrates were cleaned by an acetone ultrasonic bath. For the sake of comparison, pure fullerene and pure silicon were separately deposited in the same conditions and by the methods used for the mixed samples. Also, in some samples pure fullerene and C 60 -Si were simultaneously deposited in different zones of the substrate, in order to compare the thermal stability of each material under the same conditions.Both pure fullerene and fullerene-silicon samples were analyzed by Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), Micro-Raman spectroscopy, Wide-angle X-ray scattering (WAXS) and X-ray photoelectron spectroscopy (XPS). Microscopy was carried on by a SEM Carl Zeiss NTS SUPRA 40. Raman spectra were recorded using a LabRAM HR Raman system (Horiba Jobin Yvon), equipped with a confocal microscope and a charge coupled device detector (CCD). A 100X objective lens was used, generating a 1.5 μm spot. An 1800 g/mm grating and 100 μm hole results in a 2 cm −1 spectral resolution. The 514 nm line of an Ar + laser was used as excitation source. The laser power density over the sample was between 0.4 W.mm −2 and 4 W.mm −2 . WAXS experiments were performed at INIFTA facilities using a XEUSS 1.0 equipment from XENOCS with a K α -Cu radiation micro-source. A PILATUS-100K detector was used with 13 cm sample detector distance. Onedimensional curves were obtained by integration of the 2D data using the Foxtrot program. The scattering intensity distributions as a function of the scattering angle (2θ) were obtained in the 2θ range between 3º and 39°. The samples were placed in a motorized sample holder suitable for grazing incidence measurements at room temperature. XPS experiments were made using a Multitécnica Specs equipped with a dual Ag/Al monochromatic X-ray source and a PHOIBOS 150 hemispheric analyzer in fixed analyzer transmission mode (FAT). The spectra were obtained with 30 eV energy and an Al monochromatic

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Raman scattering in amorphous silicon films

Cited by 17 publications

References 13 publications

Silicon Nanosheets: Crossover between Multilayer Silicene and Diamond-like Growth Regime

Silicon Nanosheets: Crossover between Multilayer Silicene and Diamond-like Growth Regime

Toward Universal SERS Detection of Disease Signaling Bioanalytes Using 3D Self-Assembled Nonplasmonic near-Quantum-Scale Silicon Probe

Fullerene-silicon polymerization evidence

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