Dielectric sensing by charging energy modulation in a nano-granular metal
Dielectric sensing by charging energy modulation in a nano-granular metal
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DOI：
10.1007/s00339-014-8631-9
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发表时间：
2014-12-01
影响因子：
2.7
通讯作者：
Plank, Harald
中科院分区：
文献类型：
--
作者：
Huth, Michael;Kolb, Florian;Plank, Harald
利用聚焦电子束诱导沉积制备纳米结构的传感概念在过去几年中得到了发展。介绍了基于纳米颗粒铂碳结构（Pt(C)）的应变和力传感器的研究进展。最近，纳米颗粒Pt(C)结构通过电导调制来检测吸附水层的存在的能力得到了证明。对于磁传感和应变传感，传感效应的潜在物理机制已经得到了详细的分析，现在已经很好地理解了。对于吸附层诱导的电导调制效应，情况并非如此。在这里，我们提供了一个理论框架，允许对观察到的水感应效应进行半定量的理解。我们展示了由极化吸附层的介电屏蔽引起的纳米颗粒金属中库仑充电能量的近界面重整化如何导致电导调制。该模型可以解释在水吸附实验中观察到的电导调制，也可以应用于理解纳米颗粒Pt(C)上铁电薄膜近界面介电异常引起的类似效应。我们的发现为优化纳米颗粒层结构提供了一条途径，适用于广泛的电介质或局部电位传感应用。
Several sensing concepts using nanostructures prepared by focused-electron-beam-induced deposition have been developed over the last years. Following work on highly miniaturized Hall sensors for magnetic sensing with soft magnetic Co, strain and force sensing based on nano-granular platinum-carbon structures (Pt(C)) was introduced. Very recently, the capability of nano-granular Pt(C) structures to detect the presence of adsorbate water layers by conductance modulations was demonstrated. For magnetic and strain sensing, the underlying physical mechanisms of the sensing effect have been analyzed in detail and are now quite well understood. This is not the case for the adsorbate layer-induced conductance modulation effect. Here, we provide a theoretical framework that allows for a semi-quantitative understanding of the observed water-sensing effect. We show how the near-interface renormalization of the Coulomb charging energy in the nano-granular metal caused by the dielectric screening of the polarizable adsorbate layer leads to a conductance modulation. The model can account for the conductance modulation observed in the water adsorbate experiments and can also be applied to understand similar effects caused by near-interface dielectric anomalies of ferroelectric thin films on top of nano-granular Pt(C). Our findings provide a pathway toward optimized nano-granular layer structures suitable for a wide range of dielectric or local potential sensing applications.