Computational Biological Center , IBM Thomas J. Watson Research , Yorktown Heights , New York 10598 , United States.
Nano Lett. 2019 Feb 13;19(2):977-982. doi: 10.1021/acs.nanolett.8b04208. Epub 2019 Jan 14.
Nanofluidic diodes based on nanochannels have been studied theoretically and experimentally for applications such as biosensors and logic gates. However, when analyzing attoliter-scale samples or enabling high-density integration of lab-on-a-chip devices, it is beneficial to miniaturize the size of a nanofluidic channel. Using molecular dynamics simulations, we investigate conductance of nanopores in bilayer hexagonal boron nitride (h-BN). Remarkably, we found that triangular nanopores possess excellent rectifications of ionic currents while hexagonal ones do not. It is worth highlighting that the pore length is only about 0.7 nm, which is about the atomic limit for a bipolar diode. We determined scaling relations between ionic currents I and pore sizes L for small nanopores, that are I ∼ L in a forward biasing voltage and I ∼ L in a reverse biasing voltage. Simulation results qualitatively agree with analytical ones derived from the one-dimensional Poisson-Nerst-Planck equations.
基于纳米通道的纳流二极管已在理论和实验上得到了研究，可应用于生物传感器和逻辑门等领域。然而，在分析皮升级别的样本或实现片上实验室设备的高密度集成时，将纳流通道的尺寸小型化是有益的。我们使用分子动力学模拟研究了双层六方氮化硼（h-BN）中的纳米孔的电导。值得注意的是，我们发现三角形纳米孔具有优异的离子电流整流性能，而六边形纳米孔则没有。值得强调的是，孔的长度仅约为 0.7nm，这大约是双极二极管的原子极限。我们确定了小纳米孔中离子电流 I 和孔尺寸 L 之间的缩放关系，在正向偏置电压下为 I∼L，在反向偏置电压下为 I∼L。模拟结果与从一维泊松-纳斯特-普朗克方程推导出的解析结果定性一致。
