Change of the stoichiometry and electrocoloration due to the injection of Li and O ions into lithium niobate crystals |
| |
Authors: | S Bredikhin S Scharner M Klingler V Kveder B Red'kin W Weppner |
| |
Institution: | (1) Inst. of Solid State Physics, Russian Academy of Science, 142432 Chernogolovka, Moscow Dist., Russia;(2) Chair for Sensors and Solid State Ionics, Christian-Albrechts University, Kaiserstr. 2, D-24143 Kiel., Germany |
| |
Abstract: | Congruently grown LiNbO3 single crystals show both high oxygen and lithium ion conductivity at temperatures above 500 °C. The high oxygen ion conductivity
can be understood in terms of a certain amount of oxygen vacancies already present in congruently grown LiNbO3 single crystals. Thermal treatment of LiNbO3 produces additional oxygen vacancies. The absorption bands introduced by this procedure are investigated. It is found that
the electrons which are generated during the reduction process are homogeneously distributed among all oxygen vacancies in
the LiNbO3 single crystals. The electrocoloration phenomenon in LiNbO3 single crystals is due to the process of injection of lithium ions and electrons into LiNbO3 by a double charge mechanism. Investigations of the optical and electrical properties of electrocolored LiNbO3 crystals are reported. It is shown that the absorption spectra of thermally and electrochemically reduced samples are identical
and that the origin of the absorption processes has to be therefore the same in both cases. That means, additional electrons
produced by the double charge injection of lithium ions and electrons are also homogeneously distributed among the oxygen
vacancies. This supports our hypothesis that a certain amount of oxygen vacancies has to be present already in as-grown LiNbO3 single crystals. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|