发表机构
California State University Northridge（北岭加州州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对石墨烯纳米间隙水环境界面行为表征不足的问题，通过可控电击穿制备样品，采用电化学阻抗谱结合等效电路模型，揭示其频率响应与pH依赖特性，可提取有效纳米间隙长度尺度，为相关研究提供互补信息。
AI 中文摘要
石墨烯纳米间隙是一种新兴的纳米级电化学与传感器件平台，在下一代生物分子测序领域具有潜在应用，但它们在水环境中的界面行为仍缺乏充分表征，尤其是在石墨烯边缘的频率依赖性阻抗与电荷输运机制方面。我们在惰性气氛中通过可控电击穿制备石墨烯纳米间隙并研究其电化学响应：暴露于环境条件后，表面污染层会在石墨烯边缘间吸附的超薄导电膜内支撑电化学活性；电化学阻抗谱显示出与受限界面膜中扩散相关的Warburg元件一致的独特频率依赖性响应；阻抗随液体pH值系统变化，反映了石墨烯边缘处电化学反应-扩散过程的改变；定量等效电路模型可捕捉这些效应，并能从阻抗谱中提取有效纳米间隙长度尺度，提供与隧穿测量所得信息互补的内容。
英文摘要
Graphene nanogaps represent an emerging platform for nanoscale electrochemical and sensing devices, with potential applications in next-generation biomolecular sequencing. However, their interfacial behavior in aqueous environments remains poorly characterized, particularly with respect to frequency-dependent impedance and charge transport mechanisms at the graphene edge. We fabricate graphene nanogaps by controlled electrical breakdown in an inert atmosphere and study their electrochemical response. Upon exposure to ambient conditions, a surface contamination layer supports electrochemical activity within an adsorbed ultrathin conductive film between the graphene edges. Electrochemical impedance spectroscopy reveals distinct frequency-dependent responses consistent with a Warburg element associated with diffusion in this confined interfacial film. The impedance evolves systematically with liquid $\mathrm{p}H$, reflecting changes in electrochemical reaction-diffusion processes at the graphene edges. A quantitative equivalent-circuit model captures these effects and enables extraction of an effective nanogap length scale from impedance spectra, providing information complementary to that obtained from tunneling measurements.
Comments6 pages, 3 figures
