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Novel, low-cost solid-liquid-solid process for the synthesis of α-Si3N4 nanowires at lower temperatures and their luminescence properties.

Liu H, Huang Z, Huang J, Fang M, Liu YG, Wu X, Hu X, Zhang S - Sci Rep (2015)

Bottom Line: The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism.The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source.This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Technology, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, China University of Geosciences (Beijing), 100083, P. R. China.

ABSTRACT
Ultra-long, single crystal, α-Si3N4 nanowires sheathed with amorphous silicon oxide were synthesised by an improved, simplified solid-liquid-solid (SLS) method at 1150 °C without using flowing gases (N2, CH4, Ar, NH3, etc.). Phases, chemical composition, and structural characterisation using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) showed that the nanowires had Si3N4@SiOx core-shell structures. The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism. The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source. This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties.

No MeSH data available.


Related in: MedlinePlus

The excitation and emission spectra of α-Si3N4 nanowires.The excitation spectrum monitored at 417 nm indicated two excitation peaks at 254 nm and 369 nm. The emission spectra were measured under 254 nm and 369 nm excitation, respectively.
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f6: The excitation and emission spectra of α-Si3N4 nanowires.The excitation spectrum monitored at 417 nm indicated two excitation peaks at 254 nm and 369 nm. The emission spectra were measured under 254 nm and 369 nm excitation, respectively.

Mentions: To investigate the optical properties of the as-synthesised α-Si3N4 nanowires, their PL and CL spectra were recorded at room temperature. Figure 6 shows the room temperature PL spectra of the α-Si3N4 nanowires. The excitation spectrum was taken over the range 200 to 400 nm, and was monitored at 417 nm (2.97 eV). The excitation signatures of the as-synthesised α-Si3N4 nanowires showed two distinct peaks centred around 254 nm (4.88 eV) and 369 nm (3.36 eV), respectively. Therefore, the emission spectra were recorded under these two excitation wavelengths. The results showed that the PL intensity excited at 254 nm (4.88 eV) was much higher than that excited at 369 nm (3.36 eV), and the peak position was slightly red-shifted with decreasing excitation wavelength. Strong emission spectra were located in the violet-blue spectral range, centred around 417 nm (2.97 eV) and 434 nm (2.86 eV), respectively, when excited by light with wavelengths of 254 nm (4.88 eV) and 369 nm (3.36 eV). The two emission bands were both considerably red-shifted, compared with the direct band gap of α-Si3N4 (5.2 to 5.3 eV)2230. These PL results were different from those in previous reports2941. Robertson et al. define four types of defects in Si3N4, including: Si-Si, N-N, =N0, and ≡Si0 dangling bonds. As previously reported2942, the luminescence centred at approximately 417 nm (2.97 eV) should arise due to recombination, either from the conduction band to the N20 level, or the valence band to the N4+ level. As proposed, an amorphous oxide layer existed on the surface of the α-Si3N4 nanowires, as determined by TEM/HRTEM, FT-IR, and XPS. As previously reported, the emission bands centred around 434 nm (2.86 eV) could arise from the electronic transitions from ≡Si0 to N-Si-O293043. Based on previous research, in the current results, when excited by 254 nm (4.88 eV) wavelength light, we believed that the recombination from the conduction band to the N20 level or the valence band to the N4+ level dominated the emission properties, together with the electronic transitions from ≡Si0 to N-Si-O. Nevertheless, the electronic transitions from ≡Si0 to N-Si-O dominated the emission properties when excited by light with a wavelength of 369 nm (3.36 eV).


Novel, low-cost solid-liquid-solid process for the synthesis of α-Si3N4 nanowires at lower temperatures and their luminescence properties.

Liu H, Huang Z, Huang J, Fang M, Liu YG, Wu X, Hu X, Zhang S - Sci Rep (2015)

The excitation and emission spectra of α-Si3N4 nanowires.The excitation spectrum monitored at 417 nm indicated two excitation peaks at 254 nm and 369 nm. The emission spectra were measured under 254 nm and 369 nm excitation, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660443&req=5

f6: The excitation and emission spectra of α-Si3N4 nanowires.The excitation spectrum monitored at 417 nm indicated two excitation peaks at 254 nm and 369 nm. The emission spectra were measured under 254 nm and 369 nm excitation, respectively.
Mentions: To investigate the optical properties of the as-synthesised α-Si3N4 nanowires, their PL and CL spectra were recorded at room temperature. Figure 6 shows the room temperature PL spectra of the α-Si3N4 nanowires. The excitation spectrum was taken over the range 200 to 400 nm, and was monitored at 417 nm (2.97 eV). The excitation signatures of the as-synthesised α-Si3N4 nanowires showed two distinct peaks centred around 254 nm (4.88 eV) and 369 nm (3.36 eV), respectively. Therefore, the emission spectra were recorded under these two excitation wavelengths. The results showed that the PL intensity excited at 254 nm (4.88 eV) was much higher than that excited at 369 nm (3.36 eV), and the peak position was slightly red-shifted with decreasing excitation wavelength. Strong emission spectra were located in the violet-blue spectral range, centred around 417 nm (2.97 eV) and 434 nm (2.86 eV), respectively, when excited by light with wavelengths of 254 nm (4.88 eV) and 369 nm (3.36 eV). The two emission bands were both considerably red-shifted, compared with the direct band gap of α-Si3N4 (5.2 to 5.3 eV)2230. These PL results were different from those in previous reports2941. Robertson et al. define four types of defects in Si3N4, including: Si-Si, N-N, =N0, and ≡Si0 dangling bonds. As previously reported2942, the luminescence centred at approximately 417 nm (2.97 eV) should arise due to recombination, either from the conduction band to the N20 level, or the valence band to the N4+ level. As proposed, an amorphous oxide layer existed on the surface of the α-Si3N4 nanowires, as determined by TEM/HRTEM, FT-IR, and XPS. As previously reported, the emission bands centred around 434 nm (2.86 eV) could arise from the electronic transitions from ≡Si0 to N-Si-O293043. Based on previous research, in the current results, when excited by 254 nm (4.88 eV) wavelength light, we believed that the recombination from the conduction band to the N20 level or the valence band to the N4+ level dominated the emission properties, together with the electronic transitions from ≡Si0 to N-Si-O. Nevertheless, the electronic transitions from ≡Si0 to N-Si-O dominated the emission properties when excited by light with a wavelength of 369 nm (3.36 eV).

Bottom Line: The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism.The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source.This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Technology, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, China University of Geosciences (Beijing), 100083, P. R. China.

ABSTRACT
Ultra-long, single crystal, α-Si3N4 nanowires sheathed with amorphous silicon oxide were synthesised by an improved, simplified solid-liquid-solid (SLS) method at 1150 °C without using flowing gases (N2, CH4, Ar, NH3, etc.). Phases, chemical composition, and structural characterisation using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) showed that the nanowires had Si3N4@SiOx core-shell structures. The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism. The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source. This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties.

No MeSH data available.


Related in: MedlinePlus