激光法制备纳米氮化硅及其光谱特性研究

介绍了激光诱导化学气相沉积法制备纳米氮化硅的工艺原理,通过增加正交紫外光束激励NH3分解,提高气相中n(N)/n(Si)比,从而减少产物中游离硅的浓度,制备出粒径7～15 nm的无团聚、理想化学剂量(n(N)/n(Si)=1.314)的非晶纳米氮化硅粉体.采用透射电子显微镜观察粉体形貌,并指出表面效应和量子尺寸效应导致粉体红外吸收光谱和拉曼光谱的"蓝移"和"宽化"现象.采用双光束激励的光诱导化学气相沉积法是制备高纯度纳米氮化硅粉体的理想方法.

Study on preparation and spectra characteristics of nano Si3N4 by laser method

The basic principles of silicon nitride nano-powder synthesis by laser induced chemical vapor deposition method are investigated. By adding an ultraviolet beam of light, which is perpendicular to CO2 laser, the concentration of dissociated Si atoms decreased because the n(N)/n(Si) ratio increased. The powders possess the following characteristics: high purity, ideal stoichiometry (n(N)/n(Si)=1.314) and an narrow range of size (7-15 nm). Transmission electron graph shows that the powders are nearly monodispersed. The " blue shift " and " widening " in the observed infrared spectra and Raman spectra are resulted from the surface effect and quantum size. The laser induced chemical vapor deposition method with double beam optical stimulation is a preferable way to synthesize silicon nitride nano-powder of high purity.