Ag离子注入非晶SiO2的光学吸收、拉曼谱和透射电镜研究

能量为200keV的Ag离子，以1×10¹⁶，5×10¹⁶，1×10¹⁷ cm^-2的剂量分别注入到非晶SiO₂玻璃，光学吸收谱显示：注入剂量为1×10¹⁶ cm^-2的样品的光吸收谱为洛伦兹曲线，与Mie理论模拟的曲线形状一致；注入剂量较大的5×10¹⁶，1×10¹⁷ cm^-2的谱线共振吸收增强，峰位红移并出现伴峰. 透射电镜观察分析表明，注入剂量不同的样品中形成的纳米颗粒的大小、形状、分布都不同，注入剂量较大的还会产生明显的表面溅射效应，这些因素都会影响共振吸收的峰形、峰位和峰强. 当注入剂量达到1×10¹⁷ cm^-2时，Ag纳米颗粒内部可能还形成了杂质团簇.关键词：离子注入纳米颗粒共振吸收红移

Optical absorption, Raman spectra and TEM study of Ag nanoparticles formed by ion implantation into a-SiO2

Silver nanoparticles are formed by ion implantation into amorphous silica matrix at 200 keV at room temperature with doses of 1×10¹⁶, 5×10¹⁶ and 1×10¹⁷ cm^{-2. The sizes，distributions and shapes of the silver nanoparticles in the samples were obtained by transmission electron microscopy, which is greatly influenced by the dose. The effect of size，distribution and shape of the silver nanoparticles to the optical resonant absorption peak is been discussed. Optical absorption spectra of samples implanted with 5×1016 and 1×1017Ag+ cm-2 showed absorption peaks shifted to red, the intensity of absorption peak increased and shoulder peaks appeared, compared with the absorption spectra of the sample implanted with 1×1016Ag cm-2. The red-shift of absorption peaks and the appearance of shoulder peaks are due to the increasing volume factor and the multipolar plasmon induced by the interaction of nanoparticles, respectively. Raman scattering spectroscopy indicates that there are many defects in the high-dose implanted samples. Nanocavities in the large Ag nanoparticles are discovered in the sample with the dose of 1×1017 cm-2 possibly due to the aggregation of implant-induced silicon and oxygen atoms in Ag nanoparticles.}