离子迁移LiNbO3光波导中Ag、Tl的XPS分析

本文对电场增强离子迁移法制作的LiNbO₃光波导^1]样品作了不同于已有分析方法^2,3]的X光电子能谱(XPS)分析,对不同模数正、负波导面上的Ag、Tl、Nb、O等元素进行了测定,并对波导层中所含的Ag、Tl离子进行了剖面分析.分析结果表明:电场增强离子迁移法制作的LiNbO₃波导中,Nb⁵⁺没有变价.正波导面上Ag离子的含量随盐浴时间的延长而增加,而负波导面上则无此规律.剖面分析结果表明,Ag⁺、Tl⁺离子内迁的深度为500~2500(Å);正波导面的离子分布呈现一个台阶然后再以余误差分布下降,负波导面的离子分布为余误差分布;与光学测量计算结果比较,离子内迁深度不超过波导层的1/10.

XPS ANALYSIS OF Ag AND T1 IN ION MIGRATION LINBO3 OPTICAL WAVEGUIDES

In this paper the X-ray Photoeleotron Spectroscopy (XPS) analysis on the LiNbO₃ waveguide samples is reported. The samples were prepared by ion migration enhanced by electric field. The elements such as Ag, Tl, Nb and O in the different mode number waveguide planes on both the positive and the negative sides were measured. The depth profile of Ag and Tl ions in the waveguide layer was analysed. The results show that the Nb⁺⁵ in the LiNbO₃ samples prepared by this method has no change of valency. The concentration of Ag⁺ on the positive guide side increases with the salt-bath time, but there isn't similar rule on the negative guide. The results of depth profile analysis show that the migration depth of Ag+ and Tl+ ions is about 500~2500Å. The ion distribution in the positive guide layer presents a step, then decreases as a complementary error function. Whereas the ion distribution in the negative guide layer is a complementary error function. Compared with the calculated results of optical measurement, the migration depth of the Ag⁺ and Tl⁺ ions is less than the 1/10 depth of the waveguide layer.