Maoz Rivka, Nelson Peter, Gogoi Bedanta, Burshtain Doron, Talukder Santanu, Zou Shuangyang, Sarkar Arup, Berson Jonathan, Sagiv Jacob
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel.
ACS Nano. 2024 Jul 23;18(29):18948-18962. doi: 10.1021/acsnano.4c02074. Epub 2024 Jul 9.
The direct generation of conducting paths within an insulating surface represents a conceptually unexplored approach to single-layer electrical conduction that opens vistas for exciting research and applications fundamentally different from those based on specific layered materials. Herein we report surface channels with single-layer -COOH functionality patterned on insulating -octadecyltrichlorosilane monolayers on silicon that exhibit unusual ionic-electronic conduction when equipped with ion-releasing silver electrodes. The strong dependence of charge transport in such channels on their lateral dimensions (nanosize, macro-size), the type (p, n) and resistivity (doping level) of the underlying silicon substrate, the nature of the insulating spacer layer between the conducting channel and the silicon surface, and the postpatterning chemical manipulation of channel's -COOH functionality allows designing channels with variable resistivities, ranging from that of a practical insulator to some unexpectedly low values. The unusually low resistivities displayed by channels with nanometric widths and micrometer-millimeter lengths are attributed primarily to enhanced electronic transport within ultrathin nanowire-like silver metal films formed along their conductive paths. Function-structure correlations derived from a comprehensive analysis of electrical, atomic force microscopy, and Fourier transform infrared spectral data suggest an unconventional mode of conduction in these channels, which has yet to be elucidated, apparently involving coupled ionic-electronic transport mediated and enhanced by interfacial electrical interactions with charge carriers located outside the conducting channel and separated from those carrying the measured current. These intriguing findings hint at effects akin to Coulomb pairing in the proposed mechanisms of excitonic superconductivity in interfacial nanosystems structurally related to the present metalized surface channels.
在绝缘表面直接生成传导路径代表了一种在概念上尚未探索的单层导电方法，为与基于特定层状材料的研究和应用截然不同的令人兴奋的研究及应用开辟了前景。在此，我们报告了在硅上的绝缘十八烷基三氯硅烷单分子层上图案化有单层 -COOH 官能团的表面通道，当配备离子释放银电极时，这些通道表现出异常的离子 - 电子传导。此类通道中的电荷传输强烈依赖于其横向尺寸（纳米尺寸、宏观尺寸）、底层硅衬底的类型（p 型、n 型）和电阻率（掺杂水平）、导电通道与硅表面之间绝缘间隔层的性质，以及通道 -COOH 官能团的图案化后化学处理，这使得能够设计出具有可变电阻率的通道，其范围从实际绝缘体的电阻率到一些出乎意料的低值。具有纳米宽度和微米 - 毫米长度的通道所显示的异常低电阻率主要归因于沿其导电路径形成的超薄纳米线状银金属膜内电子传输的增强。通过对电学、原子力显微镜和傅里叶变换红外光谱数据的综合分析得出的功能 - 结构相关性表明，这些通道中存在一种尚未阐明的非常规传导模式，显然涉及由与位于导电通道外部且与携带测量电流的载流子分离的电荷载流子的界面电相互作用介导和增强的耦合离子 - 电子传输。这些有趣的发现暗示了在与当前金属化表面通道结构相关的界面纳米系统中，在拟议的激子超导机制中类似于库仑配对的效应。
