Electron transport behaviour in Nb-doped SrTiO3 bicrystals.
Electron transport behaviour in Nb-doped SrTiO3 bicrystals.
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Nb 掺杂 SrTiO3 双晶中的电子传输行为。
DOI：
10.1093/jmicro/50.6.485
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Y. Ikuhara
中科院分区：
文献类型：
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作者：
T. Yamamoto;Y. Ikuhara
为了阐明电子输运行为与缺陷化学的关系，研究了掺Nb的SrTiO_3双晶的晶界结构和跨界的伏安特性。对于0.2at%和1.0at%Nb掺杂的钛酸锶，制备了两种晶界，即小角度晶界和随机晶界。将两个单晶在1400℃、0.4 Mpa的空气压力下连接10h，制备了双晶。高分辨电子显微镜(HRTEM)研究表明，所有连接的边界都没有任何第二相或非晶膜。另一方面，研究发现，0.2at%Nb掺杂的SrTiO_3双晶加入小角度晶界后，随着降温速率的降低，其电流-电压关系的非线性变得显著。此外，1.0at%Nb掺杂的SrTiO_3双晶的无规边界表现出明显的α=2的I-V关系，这种关系出现在半导体-绝缘体-半导体(n-i-n)的接触面上。从HRTEM研究结果和I-V行为可以看出，电子输运机制主要由缺陷化学控制，而不是由晶界结构控制。
In order to elucidate the relationship between electron transport behaviour and defect chemistry, grain boundary structure and current-voltage characteristics across the boundary were investigated for Nb-doped SrTiO3 bicrystals. Two kinds of boundaries, i.e. small angle and random boundaries, were prepared for 0.2at% and 1.0at% Nb-doped SrTiO3. The bicrystals were prepared by joining two single crystals at 1400 degrees C for 10 h under a pressure of 0.4 MPa in air. High-resolution transmission electron microscopy (HRTEM) study revealed that all of the joined boundaries are free from any secondary phases or amorphous films. On the other hand, it was found that non-linearity in current-voltage dependence becomes remarkable by reduction of cooling rate after joining in small angle boundaries of 0.2at% Nb-doped SrTiO3 bicrystal. In addition, the random boundary of 1.0at% Nb-doped SrTiO3 bicrystal exhibits clear alpha = 2 I-V relation, which appears across a contact of semiconductor-insulator-semiconductor (n-i-n). From the results of HRTEM study and I-V behaviours, it could be concluded that the electron transport mechanism is controlled mainly by defect chemistry and not by the grain boundary structure.