College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, China.
Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
Int J Mol Sci. 2018 Sep 6;19(9):2639. doi: 10.3390/ijms19092639.
Graphene-based nanopore devices have shown tantalizing potential in single molecule detection for their monoatomic membrane thickness which is roughly equal to the gap between nucleobases. However, high noise level hampers applications of graphene nanopore sensors, especially at low frequencies. In this article, we report on a study of the contribution of suspended graphene area to noise level in full frequency band. Monolayer graphene films are transferred onto SiN substrates preset with holes in varied diameters and formed self-supported films. After that, the films are perforated with smaller, nanoscale holes. Experimental studies indicate a dependency of low-frequency 1/ noise on the underlying SiN geometry. The contribution of the suspended graphene area to capacitance which affects the noise level in the high frequency range reveals that the graphene free-standing film area influences noise level over a wide frequency region. In addition, the low-frequency noise demonstrates a weak dependency on salt concentration, in deviation from Hooge's relation. These findings and attendant analysis provide a systematic understanding of the noise characteristics and can serve as a guide to designing free-standing monolayer graphene nanopore devices.
基于石墨烯的纳米孔器件因其单原子膜的厚度（大致等于碱基对之间的间隙）而在单分子检测中显示出诱人的潜力。然而，高噪声水平阻碍了石墨烯纳米孔传感器的应用，尤其是在低频下。在本文中，我们报告了在全频带中研究悬浮石墨烯面积对噪声水平的贡献。单层石墨烯薄膜转移到 SiN 衬底上，衬底上预先设有不同直径的孔，并形成自支撑膜。之后，用更小的纳米级孔穿孔。实验研究表明低频 1/噪声与底层 SiN 几何形状有关。悬浮石墨烯面积对电容的贡献会影响高频范围内的噪声水平，这表明在较宽的频率范围内，无支撑石墨烯自由膜面积会影响噪声水平。此外，低频噪声与 Hooge 关系的偏差表现出对盐浓度的弱依赖性。这些发现和相关分析提供了对噪声特性的系统理解，并可作为设计独立的单层石墨烯纳米孔器件的指导。
