Behaviour of acceptor states in semiconducting BaTiO3 and SrTiO3

Kutty, TRN (1986) Behaviour of acceptor states in semiconducting BaTiO3 and SrTiO3. In: Proceedings of the Indian Academy of Sciences - Chemical Sciences, 96 (6). 581 -597.

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Abstract

The semiconductivity inMTiO3 (M=Ba, Sr) in the temperature range of practical applications is greatly influenced by the electronic charge redistribution among the acceptor states, arising from the frozen cation vacancies as well as the transition metal ion impurities. The conductivity measurements and defect chemistry investigations above 800 K indicate that the predominant lattice defects areM− and oxygen vacancies. There is dominantp-type conduction at higherP O 2 values in acceptor doped materials at high temperatures. However, they are insulating solids around room temperature due to the redistribution of electrons between the neutral, singly-or doubly-ionised acceptor states. Results fromepr and resistivity measurements show that the above charge redistribution is dependent on crystal structure changes. Hence the electron or hole loss by the acceptor states is influenced by the soft modes which also accounts for the differences in electrical properties of BaTiO3 and SrTiO3. The results are also useful in explaining the positive temperature coefficient in resistance and some photo-electrochemcial properties of these solids.

Item Type:	Journal Article
Publication:	Proceedings of the Indian Academy of Sciences - Chemical Sciences
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	BaTiO3;SrTiO3;semiconductivity in perovskites;acceptor states.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	27 Aug 2009 10:38
Last Modified:	19 Sep 2010 05:39
URI:	http://eprints.iisc.ac.in/id/eprint/21957

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