LICVD法制备纳米Si3N4粒子及红外光谱特性

采用激光诱导化学气相沉积法制备出超细（7～15nm）、理想化学剂量（N／Si=1．314）、无团聚的非晶纳米氮化硅粉体．为了提高粉体的纯度,在传统激光诱导化学气相沉积装置中加一束正交的紫外光束．以促进NH3分子光解,从而减少游离硅的存在,提高N／Si原子数比．观察到了红外吸收光谱中的“蓝移”和“宽化”现象．并认为这些现象是由表面效应和量子尺寸效应造成的．同时,红外吸收光谱的反常现象也验证了粉体的纳米特性．

Preparation of Si3N4 nano-powders produced by laser induced chemical vapor deposition and its IR absorption spectra of the powders

By using laser induced chemical vapor deposition method,amorphous silicon nitride nano-powders were prepared.The powders showed the following characteristics: ultra-fine(7-15 nm),ideal stoichiometry(N/Si=1.314) and monodispersed.In order to increase the purity of the powder,an perpendicular ultraviolet beam of light was added to the traditional laser induced chemical vapor deposition equipment to promote the photodissociatioll of NH3 molecules,increase the N/Si ratio,and reduce the concentration of free Si atoms.The "Blue Shift" and "Widening" in the Infrared spectra were observed which was considered as resulted from the surface effect and quantum size.Simultaneously,these abnormal phenomena in infrared absorption spectra approved that the powders are characterized by nano dimension.