整改
材料科学
阻挡层
氧化物
阳极氧化
离子键合
电流(流体)
氧化铝
图层(电子)
阳极
多孔性
阳极氧化铝
铝
化学工程
无机化学
纳米技术
复合材料
离子
化学
冶金
制作
电极
电压
物理化学
有机化学
替代医学
量子力学
医学
病理
工程类
物理
电气工程
作者
Yun Do Kim,Seungwook Choi,Ansoon Kim,Woo Lee
出处
期刊:ACS Nano
[American Chemical Society]
日期:2020-09-15
卷期号:14 (10): 13727-13738
被引量:22
标识
DOI:10.1021/acsnano.0c05954
摘要
Synthetic nanofluidic diodes with highly nonlinear current-voltage characteristics are currently of particular interest because of their potential applications in biosensing, separation, energy harvesting, and nanofluidic electronics. We report the ionic current rectification (ICR) characteristics of a porous anodic aluminum oxide membrane, whose one end of the nanochannels is closed by a barrier oxide layer. The membrane exhibits intriguing pH-dependent ion transport characteristics, which cannot be explained by the conventional surface charge governed ionic transport mechanism. We reveal experimentally and theoretically that the space charge density gradient present across the 40-nm-thick barrier oxide is mainly responsible for the evolution of ICR. Based on our findings, we demonstrate the formation of a single 5-8-nm-sized pore in each hexagonal cell of the barrier oxide. The present work would provide valuable information for the design and fabrication of future ultrathin nanofluidic devices without being limited by the engineering of the nanochannel geometry or surface charge.
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