离子辐照形成空心银纳米颗粒

离子辐照是控制金属纳米颗粒分布和结构的有效方法。将能量为200 keV、剂量为5×10^16ions/cm2的Ag＋注入到非晶SiO2中,形成Ag纳米颗粒层,再用能量为200和500 ke V的Ar＋辐照Ag纳米颗粒。Ar＋辐照后,在部分较大的Ag纳米颗粒中出现空洞,空洞的平均尺寸随着Ar＋辐照剂量的增加而变大。辐照前,Ag纳米颗粒在非晶SiO2中沿纵向呈近似高斯分布;辐照后,投影射程附近的较大的Ag纳米颗粒平均尺寸变大,而投影射程下面的小颗粒逐渐消失。结合Trim程序模拟分析结果可知,Ar＋辐照时的核能量损失和电子能量损失是影响Ag纳米颗粒尺寸分布和结构的重要因素。

Fabrication of hollow Ag nanoclusters in silica by Arions irradiation

Ion implantation and irradiation are suitable techniques to control the size distribution and structure of nanoclusters.In this work,Ag nanoclusters formed by implanting 200 keV Ag ions into SiO2 glass with a dose of 5×10^16 ions/cm2 were irradiated by Ar ions at 200 and 500 keV at room temperature.The cross-sectional TEM images and surface plasmon resonance absorbs spectra of the implanted and irradiated samples were studied.The results show that the nanovoids are formed in Ag nanoclusters due to aggregation of irradiation induced vacancies. When the influence of Ar ions increases,the size of nanovoids grows.Before irradiation,the distribution of Ag nanoclusters in the as-implanted sample is an approximate Gaussian profile.After irradiation,the average size of Ag nanoclusters in the layer of projected range grows and the small Ag nanoclusters below the projected range disappear gradually.The nuclear energy and electronic energy losses of Ar＋ ions are important factors that affect the size and structure of Ag nanoclusters,which are simulated by the SUSPRE program.