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Large-scale Synthesis of β -SiC Nanochains and Their Raman/Photoluminescence Properties

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ABSTRACT

Although the SiC/SiO2 nanochain heterojunction has been synthesized, the chained homogeneous nanostructure of SiC has not been reported before. Herein, the novel β-SiC nanochains are synthesized assisted by the AAO template. The characterized results demonstrate that the nanostructures are constructed by spheres of 25–30 nm and conjoint wires of 15–20 nm in diameters. Raman and photoluminescence measurements are used to explore the unique optical properties. A speed-alternating vapor–solid (SA-VS) growth mechanism is proposed to interpret the formation of this typical nanochains. The achieved nanochains enrich the species of one-dimensional (1D) nanostructures and may hold great potential applications in nanotechnology.

No MeSH data available.


a Schematic illustration for the bottom-up C3H6 flowing through the ordered nanoporous AAO template. b The simulative carbon concentration curve upon the AAO template during the synthesis process. c The stimulant SiC nanochains.
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Figure 6: a Schematic illustration for the bottom-up C3H6 flowing through the ordered nanoporous AAO template. b The simulative carbon concentration curve upon the AAO template during the synthesis process. c The stimulant SiC nanochains.

Mentions: Herein, in order to achieve longer reaction time and higher reaction, the AAO template was placed at the bottom of the reaction chamber to prepare the SiC nanochains; we believe that the nanoporous AAO template has played a key role in the synthesis of SiC crystal. In order to interpret the formation process, a reasonable SA-VS growth mechanism is proposed and schematically shown in Figure 6. The original nucleate and growth of the SiC crystal could be induced by the micro-particles of Si, SiO2 and surface defects of AAO template via a traditional VS growth mechanism [31]. While with the C3H6 gas flow introduced into the chamber and encountered with the AAO template, the flow direction of C3H6 gas is guided by the nanopore channels (Figure 6a). Under the controlled flow speed of C3H6 gas, it is reasonable that the concentration of carbon decomposed from C3H6 gas form a regular and alternate gradient distribution over the whole template plane. A maximum carbon concentration may probably occur over the around center of the nanopores, as the schematic simulated alternative carbon concentration curve over the template shown in Figure 6b. Thus, during the further growth of SiC nanostructure along [111] direction, the growth of SiC crystal would be definitely affected by the change of carbon concentration, the maximum concentration is convinced to induce the maximum growth speed of SiC crystal, and finally the maximum diameter of formed SiC nanochains. Correspondingly, the thinner SiC nanostructures will be obtained following the lower carbon concentration. After continuous vs growth process, the diameter alternating SiC nanochains are obtained at last, as is schematically shown in Figure 6c. Owing to the nanoporous AAO template and the controlled gaseous flow of C3H6, the SiC nanochains could be formed by the SA-VS growth mechanism. In addition, the same experiment process was also performed by the use of carbon substrate with smooth surface instead of nanoporous AAO template, only smooth SiC nanowire while no nanochain was observed. This strongly proved that proposed SA-VS growth mechanism of SiC nanochain was assisted by the nanoporous AAO template.


Large-scale Synthesis of β -SiC Nanochains and Their Raman/Photoluminescence Properties
a Schematic illustration for the bottom-up C3H6 flowing through the ordered nanoporous AAO template. b The simulative carbon concentration curve upon the AAO template during the synthesis process. c The stimulant SiC nanochains.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC3211428&req=5

Figure 6: a Schematic illustration for the bottom-up C3H6 flowing through the ordered nanoporous AAO template. b The simulative carbon concentration curve upon the AAO template during the synthesis process. c The stimulant SiC nanochains.
Mentions: Herein, in order to achieve longer reaction time and higher reaction, the AAO template was placed at the bottom of the reaction chamber to prepare the SiC nanochains; we believe that the nanoporous AAO template has played a key role in the synthesis of SiC crystal. In order to interpret the formation process, a reasonable SA-VS growth mechanism is proposed and schematically shown in Figure 6. The original nucleate and growth of the SiC crystal could be induced by the micro-particles of Si, SiO2 and surface defects of AAO template via a traditional VS growth mechanism [31]. While with the C3H6 gas flow introduced into the chamber and encountered with the AAO template, the flow direction of C3H6 gas is guided by the nanopore channels (Figure 6a). Under the controlled flow speed of C3H6 gas, it is reasonable that the concentration of carbon decomposed from C3H6 gas form a regular and alternate gradient distribution over the whole template plane. A maximum carbon concentration may probably occur over the around center of the nanopores, as the schematic simulated alternative carbon concentration curve over the template shown in Figure 6b. Thus, during the further growth of SiC nanostructure along [111] direction, the growth of SiC crystal would be definitely affected by the change of carbon concentration, the maximum concentration is convinced to induce the maximum growth speed of SiC crystal, and finally the maximum diameter of formed SiC nanochains. Correspondingly, the thinner SiC nanostructures will be obtained following the lower carbon concentration. After continuous vs growth process, the diameter alternating SiC nanochains are obtained at last, as is schematically shown in Figure 6c. Owing to the nanoporous AAO template and the controlled gaseous flow of C3H6, the SiC nanochains could be formed by the SA-VS growth mechanism. In addition, the same experiment process was also performed by the use of carbon substrate with smooth surface instead of nanoporous AAO template, only smooth SiC nanowire while no nanochain was observed. This strongly proved that proposed SA-VS growth mechanism of SiC nanochain was assisted by the nanoporous AAO template.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Although the SiC/SiO2 nanochain heterojunction has been synthesized, the chained homogeneous nanostructure of SiC has not been reported before. Herein, the novel β-SiC nanochains are synthesized assisted by the AAO template. The characterized results demonstrate that the nanostructures are constructed by spheres of 25–30 nm and conjoint wires of 15–20 nm in diameters. Raman and photoluminescence measurements are used to explore the unique optical properties. A speed-alternating vapor–solid (SA-VS) growth mechanism is proposed to interpret the formation of this typical nanochains. The achieved nanochains enrich the species of one-dimensional (1D) nanostructures and may hold great potential applications in nanotechnology.

No MeSH data available.