Role of Electrical Double Layer Structure in Ionic Liquid Gated Devices
Role of Electrical Double Layer Structure in Ionic Liquid Gated Devices
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电双层结构在离子液体门控器件中的作用
DOI：
10.1021/acsami.7b11044
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发表时间：
2017-11-22
影响因子：
9.5
通讯作者：
Balke, Nina
中科院分区：
文献类型：
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作者：
Black, Jennifer M.;Come, Jeremy;Balke, Nina
过渡金属氧化物的离子液体门控已经实现了新的状态（磁性、电子、金属绝缘体），为强相关氧化物的物理学提供了基本的见解。然而，尽管有大量的研究活动，但对于与过渡金属氧化物表面接触的液体结构的相关性，其随外加电位的演变以及与氧化物的测量电子性质的相关性知之甚少。在这里，我们用实验和理论研究了在双电层栅极的薄膜晶体管中，离子液体在半导体氧化物界面上的结构。我们发现，在非晶铟镓锌氧化物晶体管的ON和OFF状态之间的转变伴随着氧化物沟道表面反离子的致密化和优先空间取向。这个过程分为三个不同的步骤，对应于离子取向，因此，不同的电导率制度。其原因可以从存在不同离子排列时氧化物表面的表面电荷密度中找到。总的来说，从界面离子液体结构的角度阐明了场效应门控过程，这为将纳米结构与功能特性联系起来的液体门控晶体管的工作提供了前所未有的见解。这些知识将使新的离子液体设计以及先进的设备概念成为可能。
Ionic liquid gating of transition metal oxides has enabled new states (magnetic, electronic, metal insulator), providing fundamental insights into the physics of strongly correlated oxides. However, despite much research activity, little is known about the correlation of the structure of the liquids in contact with the transition metal oxide surface, its evolution with the applied electric potential, and its correlation with the measured electronic properties of the oxide. Here, we investigate the structure of an ionic liquid at a semiconducting oxide interface during the operation of a thin film transistor where the electrical double layer gates the device using experiment and theory. We show that the transition between the ON and OFF states of the amorphous indium gallium zinc oxide transistor is accompanied by a densification and preferential spatial orientation of counterions at the oxide channel surface. This process occurs in three distinct steps, corresponding to ion orientations, and consequently, regimes of different electrical conductivity. The reason for this can be found in the surface charge densities on the oxide surface when different ion arrangements are present. Overall, the field-effect gating process is elucidated in terms of the interfacial ionic liquid structure, and this provides unprecedented insight into the working of a liquid gated transistor linking the nanoscopic structure to the functional properties. This knowledge will enable both new ionic liquid design as well as advanced device concepts.