Grain Boundary Chemistry and Electrical Characteristics of Semiconducting <TEX>$SrTiO_3$</TEX> Ceramics Synthesized from Surface-Coated Powders

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J. Korean Ceram. Soc. > Volume 36(11); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(11): 1252.

표면 코팅된 분말을 이용하여 제조된 반도성 $SrTiO_3$ 소결체의 입계화학과 전기적 특성

박명범, 김정돈¹, 허현, 조남희

인하대학교 무기재료공학과
¹한국과학기술연구원 세라믹스 연구부

Grain Boundary Chemistry and Electrical Characteristics of Semiconducting $SrTiO_3$ Ceramics Synthesized from Surface-Coated Powders

ABSTRACT

The defect chemistry and electrical characteristics of the grain boundaries of semiconducting SrTiO3 ceramics synthesized with wet-chemically surface-coated powders were investigated. The starting powders were separated into groups of 1-10${mu}{textrm}{m}$ 10-20${mu}{textrm}{m}$ etc by sedimentation and sieving methods. Na+ ions were absorbed on the powder surfaces by wet chemical-treatment method. The width of the grain boundary ranged up to several nm and the intergranular materials was amorphous. The additives coated on the surface of the powders were observed to be present at the grain boundaries of the ceramics. The diffusion depth of the additives into grains was about 30nm for the SrTiO3 ceramics synthesized with 5w/o coated materials, The threshold voltage grain boundary resistance and boundary potential barrier of the ceramics increased from 0.67V/cm 2.27k$Omega$ and 0.05eV to 80.9V/cm 13.0k$Omega$ 1.44eV with increasing the amount of the additives from 0 to 5 w/o respectively .

Key words: $SrTiO_3$, Semiconducting Grain boundary, Boundary potential barrier