激光诱导化学气相沉积法制备纳米a-Si_3N_4粉体及粉体光谱特性的研究

Research on Preparation of Silicon Nitride Nano-powders with Laser Induced Chemical Vapor Deposition and Optical Characteristics of Powders

为了制备高纯度的非晶纳米粉体 ,在传统的激光诱导化学气相沉积法反应装置的基础上 ,引入“双光束激励”的新方法 ,利用正交紫外光束激励分解 ,从而提高气相中N/Si比 ,减少产物中游离硅的浓度。研究了粒子的红外吸收光谱特性 ,并指出表面效应和量子尺寸效应导致粉体红外吸收光谱的蓝移和宽化现象 ,同时红外吸收光谱中的这些反常现象也验证了粉体的纳米特性。

In order to increase the purity of the powder, an perpendicular ultraviolet beam of light is added to the traditional laser induced chemical vapor deposition equipment. The NH_3 molecules photondissociated and the N/Si ratio increased because the concentration of dissociated Si atoms decreased. The powders were investigated by TEM,XRD and infrared absorption spectra. The 'Blue Shift' and 'Widening' in the Infrared spectra were observed which was considered resulted from the surface effect and quantum size. Simultaneously, these abnormal phenomena in infrared absorption spectra approved that the powders have nano characteristics.