Carrier transport in mesoscopic assemblies: Bridging nano and macro.

Mario Hofmann^1*, Ya-Ping Hsieh²

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Institute for Atomic and Molecular Sciences, Academia Sinica, Taipei City, Taiwan

* Presenter:Mario Hofmann, email:mario@phys.ntu.edu.tw

Mesoscopic assemblies are of significance in next generation energy storage devices, sensors, and low cost transistors. We here present our latest advances in producing improved mesoscopic assemblies and understanding the connection between nanoscale properties and macroscale performance. Characterization of carrier transport in nanomaterials assemblies is hindered by limitations of existing metrology tools and incomplete understanding of the underlying mechanism. Traditional investigation approaches rely on indirect methods based on many samples and on simplifying assumptions which cannot reproduce the complexity of experimental results.
I will introduce several approaches to understand and apply the peculiarities of electron motion in such discontinuous media. The direct extraction of characteristic parameters from a single sample is demonstrated by analyzing the strain-dependent resistance of percolative materials. An analytical model is derived that can explain experimental data for various percolative materials, morphologies, and straining conditions. The relationship of the extracted parameters with previously introduced figures of merit allows us to compare nanostructures of diverse dimensionalities and compositions for applications in strain gauges and transparent conductors. We furthermore introduce a powerful and user-friendly network-graph based modeling approach that allows the computation of electrical conductivities for arbitrary element shapes and properties. This new simulation tool permits extrapolation towards the properties of the nanoscale constituents from measurements on macroscopic ensembles. The gained understanding is applied to enhancing the performance of transparent conductors and to realize sensors with size-independent device performance.

Keywords: Carrier transport, 2D materials, mesoscopic, sensors, simulation