熔态GeO_2结构的XAFS研究

Structure of molten GeO_2 probed by XAFS

GeO_2是光电领域内的重要材料,也是玻璃形成体基础材料之一。晶体GeO_2有六方对称的石英结构(q-GeO_2)和四面体对称的金红石结构(r-GeO_2)。前者是重要的压电和光学材料,后者是半导体Ge的良好封装材料。两种晶态GeO_2的熔点不同:q-GeO_2的熔点为1115℃,而r-GeO_2的熔点为1086℃。本工作解决了高温氧化物熔体XAFS实验中的困难,尝试了高温熔体XAFS实验的一种新的实验方法,采集了两种晶体形态GeO_2熔化后不同温度的XAFS谱,并对照晶体和非晶体的室温XAFS谱,探讨了不同结构状态的熔体不同温度下的结构及其关联,特别是两种熔点之间的熔体结构状态。

There are two types of morphologies of crystalline GeO2: quartz type (q-GeO2) and rutile type (r-GeO2) . The former is a good piezoelectric and optical material and the latter is important in electronics. The melting points of the two kinds of GeO2 are different: 1115℃ for q-GeO2 while 1086℃ for r-GeO2. We proposed a method to overcome the difficulties in the XAFS measurements for oxide melts under high temperature and have collected the XAFS spectra with high quality for molten q-GeO2 and r-GeO2. The structures of different melts from different crystalline solids and their correlation have been discussed, especially for temperatures between the two melting points.