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Grassy Silica Nanoribbons and Strong Blue Luminescence

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ABSTRACT

Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

No MeSH data available.


AES characterization of silica nanoribbons.(a) Scanning secondary electron image of the sample, showing the locations of AES spectra acquiring area. (b) Differential AES spectra acquired at positions “1”, “2” and “3” marked in (a). (c) Scanning secondary electron image of the sample, showing the locations of AES mapping. (d) Si LVV Auger electron map acquired in (c). (e) O KLL Auger electron map acquired in (c). The oval in (c) marks movement of the nanoribbon under electron-beam as compared to the positions observed in (d,e).
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f2: AES characterization of silica nanoribbons.(a) Scanning secondary electron image of the sample, showing the locations of AES spectra acquiring area. (b) Differential AES spectra acquired at positions “1”, “2” and “3” marked in (a). (c) Scanning secondary electron image of the sample, showing the locations of AES mapping. (d) Si LVV Auger electron map acquired in (c). (e) O KLL Auger electron map acquired in (c). The oval in (c) marks movement of the nanoribbon under electron-beam as compared to the positions observed in (d,e).

Mentions: We characterized the chemical composition and Si oxidation states of the silica nanoribbons by employing local scanning Auger electron spectroscopy (AES) technique16202122. The Si LVV AES peak position and shape are extremely sensitive to the Si oxidation state21. The main peak for elemental Si is centered around 90 eV while that for SiO2 is located at 76 eV2123. Figure 2b depicts the AES spectra acquired at different sample locations in Fig. 2a. At the substrate region, i.e., #1 position, the Auger electron signals of both the elemental Si and the Si oxidation states for SiO2 were detected. By contrast, only the latter was detected on the nanoribbons, i.e., #2 and #3 positions. Figure 2c,e show the Auger electron maps of the Si LVV (Fig. 2d) and O KLL (Fig. 2e), elucidating the chemical distribution of the elements in the silica nanoribbons. Besides, the X-ray photoelectron spectroscopy (XPS) results corroborate the formation of silica nanoribbons (Figure S3, Supp. Info.). Raman spectrum (Figure S4, Supp. Info.) and Fourier transform infrared spectroscopy (FTIR) (Figure S5, Supp. Info.) techniques were also used to analysized the silica nanoribbons in ambient air.


Grassy Silica Nanoribbons and Strong Blue Luminescence
AES characterization of silica nanoribbons.(a) Scanning secondary electron image of the sample, showing the locations of AES spectra acquiring area. (b) Differential AES spectra acquired at positions “1”, “2” and “3” marked in (a). (c) Scanning secondary electron image of the sample, showing the locations of AES mapping. (d) Si LVV Auger electron map acquired in (c). (e) O KLL Auger electron map acquired in (c). The oval in (c) marks movement of the nanoribbon under electron-beam as compared to the positions observed in (d,e).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5035931&req=5

f2: AES characterization of silica nanoribbons.(a) Scanning secondary electron image of the sample, showing the locations of AES spectra acquiring area. (b) Differential AES spectra acquired at positions “1”, “2” and “3” marked in (a). (c) Scanning secondary electron image of the sample, showing the locations of AES mapping. (d) Si LVV Auger electron map acquired in (c). (e) O KLL Auger electron map acquired in (c). The oval in (c) marks movement of the nanoribbon under electron-beam as compared to the positions observed in (d,e).
Mentions: We characterized the chemical composition and Si oxidation states of the silica nanoribbons by employing local scanning Auger electron spectroscopy (AES) technique16202122. The Si LVV AES peak position and shape are extremely sensitive to the Si oxidation state21. The main peak for elemental Si is centered around 90 eV while that for SiO2 is located at 76 eV2123. Figure 2b depicts the AES spectra acquired at different sample locations in Fig. 2a. At the substrate region, i.e., #1 position, the Auger electron signals of both the elemental Si and the Si oxidation states for SiO2 were detected. By contrast, only the latter was detected on the nanoribbons, i.e., #2 and #3 positions. Figure 2c,e show the Auger electron maps of the Si LVV (Fig. 2d) and O KLL (Fig. 2e), elucidating the chemical distribution of the elements in the silica nanoribbons. Besides, the X-ray photoelectron spectroscopy (XPS) results corroborate the formation of silica nanoribbons (Figure S3, Supp. Info.). Raman spectrum (Figure S4, Supp. Info.) and Fourier transform infrared spectroscopy (FTIR) (Figure S5, Supp. Info.) techniques were also used to analysized the silica nanoribbons in ambient air.

View Article: PubMed Central - PubMed

ABSTRACT

Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

No MeSH data available.