Limits...
Grassy Silica Nanoribbons and Strong Blue Luminescence

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.


Electron irradiation effect on CL spectrum of silicon nanoribbons.(a) Evolution of CL spectrum with electron irradiation time. (b) Intensity change of UV band, blue band, and red band.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5035931&req=5

f5: Electron irradiation effect on CL spectrum of silicon nanoribbons.(a) Evolution of CL spectrum with electron irradiation time. (b) Intensity change of UV band, blue band, and red band.

Mentions: We investigated the CL properties of a gathering of silica nanoribbons as a function of irradiation time (Fig. 5). The CL emission was excited by continuous irradiation over the observation field with an electron beam of energy 5.0 keV and current 0.1 nA. The very weak green emission of the first collected CL spectrum might be due to the relatively small substrate area because irradiated area is almost fully covered by the silica nanoribbons and silicon aggregates responsible for the emission is not as sensitive to the irradiation as the OVCs. The intensity of the red emission increased with the irradiation time from 0 s to about 600 s; and the UV emission first increased and then decreased within the first 300 s. In the case of the blue emission, the intensity escalated rapidly to a constant intensity within the first 240 s. With irradiation, green emission was being overlapped by the strong blue emission. The trend of the irradiation effect on the luminescence of the nanoribbons is similar to the previous observations on amorphous SiO2 films41. Nevertheless, the previous amorphous SiO2 films41 did not possess the green emission as detected on our substrate, and we also failed to observe the blue emission from the substrate. The different behaviours of the UV and blue emissions upon the electron irradiation indicate different origins of the emissions. These results indicate that the electron irradiation significantly increases the number of luminescent centers of the silica nanoribbons, strongly dependent on their stoichiometries or absolute deficiency of oxygen atoms over silicon atoms4748.


Grassy Silica Nanoribbons and Strong Blue Luminescence
Electron irradiation effect on CL spectrum of silicon nanoribbons.(a) Evolution of CL spectrum with electron irradiation time. (b) Intensity change of UV band, blue band, and red band.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Electron irradiation effect on CL spectrum of silicon nanoribbons.(a) Evolution of CL spectrum with electron irradiation time. (b) Intensity change of UV band, blue band, and red band.
Mentions: We investigated the CL properties of a gathering of silica nanoribbons as a function of irradiation time (Fig. 5). The CL emission was excited by continuous irradiation over the observation field with an electron beam of energy 5.0 keV and current 0.1 nA. The very weak green emission of the first collected CL spectrum might be due to the relatively small substrate area because irradiated area is almost fully covered by the silica nanoribbons and silicon aggregates responsible for the emission is not as sensitive to the irradiation as the OVCs. The intensity of the red emission increased with the irradiation time from 0 s to about 600 s; and the UV emission first increased and then decreased within the first 300 s. In the case of the blue emission, the intensity escalated rapidly to a constant intensity within the first 240 s. With irradiation, green emission was being overlapped by the strong blue emission. The trend of the irradiation effect on the luminescence of the nanoribbons is similar to the previous observations on amorphous SiO2 films41. Nevertheless, the previous amorphous SiO2 films41 did not possess the green emission as detected on our substrate, and we also failed to observe the blue emission from the substrate. The different behaviours of the UV and blue emissions upon the electron irradiation indicate different origins of the emissions. These results indicate that the electron irradiation significantly increases the number of luminescent centers of the silica nanoribbons, strongly dependent on their stoichiometries or absolute deficiency of oxygen atoms over silicon atoms4748.

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.