Abstract

Fluctuations of the ion current in elastic nanopores are studied in a wide frequency range and a complete description of their noise characteristics is presented. The lumen of ultrashort (<200 nm) lipid nanotubes (usNT) filled with an electrolyte solution was used as a model of an elastic nanopore. It is shown that at low frequencies (f < 300 Hz) the 1/f noise type prevails. This low frequency noise was analyzed at different salt concentrations and nanopore geometries and it was found that the 1/f noise power is proportional to the reciprocal of the number of charge carriers, which is in good agreement with the empirical Hooge relation. Linear approximation showed that the Hooge parameter for elastic nanopores is (2.5 ± 0.5) × 10^–3, which turned out to be an order of magnitude higher than for solid analogs. In the high-frequency regime (f > 1 kHz), white noise becomes dominant, the power density of which depends linearly on the signal bandwidth and, as the length of the usNT decreases and the ionic strength increases, it is in good agreement with its representation as the sum of the Johnson–Nyquist thermal noise and the Schottky shot noise.

中文翻译：

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超短弹性膜纳米管中的噪声

摘要

研究了宽频率范围内弹性纳米孔中离子电流的波动，并对其噪声特性进行了完整描述。充满电解质溶液的超短 (<200 nm) 脂质纳米管 (usNT) 的管腔被用作弹性纳米孔的模型。结果表明，在低频 ( f < 300 Hz) 下，1/ f噪声类型占优势。在不同的盐浓度和纳米孔几何形状下分析这种低频噪声，发现 1/ f噪声功率与电荷载流子数量的倒数成正比，这与经验 Hooge 关系非常吻合。线性近似表明弹性纳米孔的 Hooge 参数为 (2.5 ± 0.5) × 10 ^–3，结果证明比固体类似物高一个数量级。在高频区域（f  > 1 kHz），白噪声占主导地位，其功率密度与信号带宽呈线性关系，并且随着 usNT 长度的减小和离子强度的增加，它与它表示为约翰逊-奈奎斯特热噪声和肖特基散粒噪声的总和。