采用热裂解聚合物前驱体法制备出了具有竹节结构的Si B C N纳米材料。扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明样品具有特殊的竹节状(叠杯状)形貌,电子散射能谱(EDX)证实了样品组分为Si、B、C、N。通过微区喇曼光谱仪研究了...采用热裂解聚合物前驱体法制备出了具有竹节结构的Si B C N纳米材料。扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明样品具有特殊的竹节状(叠杯状)形貌,电子散射能谱(EDX)证实了样品组分为Si、B、C、N。通过微区喇曼光谱仪研究了样品在488nm激光激发下从84～290K的变温发射特性,在490～800nm观察到位于580,620nm附近两个较强发射峰和740nm附近一个弱的发射峰。变温实验说明相应发射峰与材料禁带中形成的杂质能级有关。展开更多
The dielectric properties of nano Si/C/N composite powder and nano SiC powder at high frequencies have been studied. The nano Si/C/N composite powder and nano SiC powder were synthesized from hexamethyldisilazane ((Me...The dielectric properties of nano Si/C/N composite powder and nano SiC powder at high frequencies have been studied. The nano Si/C/N composite powder and nano SiC powder were synthesized from hexamethyldisilazane ((Me 3Si) 2NH) (Me:CH 3) and SiH 4 C 2H 2 respectively by a laser induced gas phase reaction. The complex permittivities of the nano Si/C/N composite powder and nano SiC powder were measured between 8 2GHz and 12 4GHz. The real and imaginary parts of the complex permittivities of nano Si/C/N composite powder are much higher than those of nano SiC powder. The SiC microcrystalline in the nano Si/C/N composite powder dissolved a great deal of nitrogen. The local structure around Si atoms changed by introducing N into SiC. Carbon atoms around Si were substituted by N atoms. So charged defects and quasi free electrons moved in response to the electric field, diffusion or polarization current resulted from the field propagation. The high ε″and loss factor tgδ(ε″/ε′) of Si/C/N composite powder were due to the dielectric relaxation.展开更多
文摘采用热裂解聚合物前驱体法制备出了具有竹节结构的Si B C N纳米材料。扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明样品具有特殊的竹节状(叠杯状)形貌,电子散射能谱(EDX)证实了样品组分为Si、B、C、N。通过微区喇曼光谱仪研究了样品在488nm激光激发下从84～290K的变温发射特性,在490～800nm观察到位于580,620nm附近两个较强发射峰和740nm附近一个弱的发射峰。变温实验说明相应发射峰与材料禁带中形成的杂质能级有关。
文摘The dielectric properties of nano Si/C/N composite powder and nano SiC powder at high frequencies have been studied. The nano Si/C/N composite powder and nano SiC powder were synthesized from hexamethyldisilazane ((Me 3Si) 2NH) (Me:CH 3) and SiH 4 C 2H 2 respectively by a laser induced gas phase reaction. The complex permittivities of the nano Si/C/N composite powder and nano SiC powder were measured between 8 2GHz and 12 4GHz. The real and imaginary parts of the complex permittivities of nano Si/C/N composite powder are much higher than those of nano SiC powder. The SiC microcrystalline in the nano Si/C/N composite powder dissolved a great deal of nitrogen. The local structure around Si atoms changed by introducing N into SiC. Carbon atoms around Si were substituted by N atoms. So charged defects and quasi free electrons moved in response to the electric field, diffusion or polarization current resulted from the field propagation. The high ε″and loss factor tgδ(ε″/ε′) of Si/C/N composite powder were due to the dielectric relaxation.
