The Institute of Scientific and Industrial Research, Osaka University, Japan.
Nanoscale. 2019 Mar 7;11(10):4190-4197. doi: 10.1039/c8nr09042d.
We investigated the roles of silicon substrate material compositions in ionic current blockade in solid-state nanopores. When detecting single nanoparticles using an ionic current in a Si3N4 nanopore supported on a doped silicon wafer, resistive pulses were found to be blunted significantly via signal retardation due to predominant contributions of large capacitance at the ultrathin membrane. Unexpectedly, in contrast, changing the substrate material to non-doped silicon led to the sharpening of the spike-like signal feature, suggesting a better temporal resolution of the cross-channel ionic current measurements by virtue of the thick intrinsic semiconductor layer that served to diminish the net chip capacitance. The present results suggest the importance of the choice of Si compositions regarding the capacitance effects to attain better spatiotemporal resolution in solid-state nanopore sensors.
我们研究了硅衬底材料成分在固态纳米孔中离子电流阻断中的作用。当在掺杂硅片上支撑的 Si3N4 纳米孔中使用离子电流检测单个纳米颗粒时，发现由于超薄膜中大电容的主要贡献，电阻脉冲由于信号延迟而明显变钝。出乎意料的是，相比之下，将衬底材料改为非掺杂硅会导致尖峰状信号特征变锐，这表明由于厚的本征半导体层减小了总芯片电容，从而改善了跨通道离子电流测量的时间分辨率。目前的结果表明，在固态纳米孔传感器中实现更好的时空分辨率，选择硅成分对于电容效应的重要性。
