【摘要】 采用聚硅氮烷前驱体热裂解方法制备S iC纳米棒,并利用SEM、XRD和EDX表征了S iC纳米棒的结构和组成,表明得到的S iC的组分比C∶S i接近1∶1。用微区Ram an和光致发光方法研究了纳米棒的光学性质。观测到S iC的TO模式对应的Ram an峰和相邻肩峰。对S iC纳米棒观测到其紫外3.25 eV附近强的光致发光峰,我们认为它归结为α型S iC带间的跃迁。通过XRD、Ram an和光发射谱,我们推测前驱体热裂解得到的S iC纳米棒是一个混晶,纳米棒的表层是立方晶,而内层主要为a-S iC。更多还原

【Abstract】 Silicon carbide nano-rods was synthesized by the pyrolysis of a polysilazane preceramic precursor in the presence of 3%（mass fraction） FeCl₂ as a catalyst under 1 700 ℃.SEM,XRD and EDX was employed to characterize their structure and component.XRD pattern demonstrated that nano-rods consist of 3C-SiC as a sole type of crystalline with a plenty of stack fault,and no trace indicated a-SiC polytypes.The ratio of silicon and carbon is estimated as close to 1∶1 based on EDX semiquantitative estimation. Electron microscopy results revealed that the SiC nanorods of 80～200 nm in diameter and several hundred micrometers to a few millimeters in length preferentially grow along（111） direction.Optical properties of nanorods were studied using（micro-Raman） spectrum,photoluminescence and optical band edge Absorption.In PL spectra an intensive（emission） at 3.27 eV was observed,and a weak broad emission band was located at low energy side about 2.4 eV,while the（optical） Absorption spectra revealed that there is an optical Absorption edge at the identical energy（level） mentioned above.However,the optical Absorption spectra showed a complex structure.In order to get more definite information,Raman spectra were measured on these SiC nanorods.Raman spectrum gives a sharp scattering peak at near 800 cm^-1 with a shoulder multiply peak at low energy side.Using Gaussian peak fitting,we found that it contains two peaks at 799.6 and 777 cm^-1,corresponding to the TO mode for 3C-SiC and a-SiC respectively.Basis of the results of XRD,Raman,optical Absorption and PL emission,we conduced to one supposition that the SiC nanorods are mixing-polycrystal with a multi-layer structure.更多还原