ISSN:
1862-0760
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02375728
