Probing vacancy behavior across complex oxide heterointerfaces
Probing vacancy behavior across complex oxide heterointerfaces
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DOI：
10.1126/sciadv.aau8467
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发表时间：
2019-02
期刊：
影响因子：
13.6
通讯作者：
Jiaxin Zhu;Jungwoo Lee;Hyungwoo Lee;L. Xie;Xiaoqing Pan;R. D. De Souza;C. Eom;S. Nonnenmann
中科院分区：
文献类型：
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作者：
Jiaxin Zhu;Jungwoo Lee;Hyungwoo Lee;L. Xie;Xiaoqing Pan;R. D. De Souza;C. Eom;S. Nonnenmann
沉积过程引起的衬底支撑氧化物薄膜中空位分布的实时探针轮廓变化。氧空位（VO··）作为复合氧化物中的缺陷在包括忆阻器、全氧化物电子器件和包括金属-绝缘体-金属或复合氧化物异质结构配置的电化学电池的系统中建立功能中起关键作用。改善氧化物-氧化物界面需要对限定电化学活性区域的空位分布有直接的空间理解。我们发现，由于沉积和后退火过程中的铌掺杂的SrTiO 3（Nb：SrTiO 3）基板的空位耗尽超过微米级的距离。我们使用（T = 500°C）原位扫描探针和半导体分析将钛酸锶/氧化钇稳定的氧化锆（STO/YSZ）异质结构膜的表面电势转换为STO内的空间（<100 nm）空位分布。在脉冲激光沉积期间发生的氧清除基本上减少Nb：STO，其在冷却时在富氧环境中部分再氧化。这些结果（i）介绍的手段，以空间解决定量空位分布的氧化物薄膜和（ii）表示的机制，氧化物薄膜增强，然后耗尽下面的基板内的空位。
Real-time probes profile changes in vacancy distributions within substrate-supported oxide films induced by deposition processes. Oxygen vacancies (VO••) play a critical role as defects in complex oxides in establishing functionality in systems including memristors, all-oxide electronics, and electrochemical cells that comprise metal-insulator-metal or complex oxide heterostructure configurations. Improving oxide-oxide interfaces necessitates a direct, spatial understanding of vacancy distributions that define electrochemically active regions. We show vacancies deplete over micrometer-level distances in Nb-doped SrTiO3 (Nb:SrTiO3) substrates due to deposition and post-annealing processes. We convert the surface potential across a strontium titanate/yttria-stabilized zirconia (STO/YSZ) heterostructured film to spatial (<100 nm) vacancy profiles within STO using (T = 500°C) in situ scanning probes and semiconductor analysis. Oxygen scavenging occurring during pulsed laser deposition reduces Nb:STO substantially, which partially reoxidizes in an oxygen-rich environment upon cooling. These results (i) introduce the means to spatially resolve quantitative vacancy distributions across oxide films and (ii) indicate the mechanisms by which oxide thin films enhance and then deplete vacancies within the underlying substrate.