The electrical conduction of nanostructured Sn films assembled via Supersonic Cluster Beam Deposition is studied in-situ during film growth. The kinetic energy of Sn nanoparticles, in combination with low melting point of Sn, promotes coalescence phenomena, enabling the investigation of their impact on film morphology and on percolation threshold. A percolation threshold occurring at thicknesses much larger than the dimensions of Sn nanoparticles suggests that coalescence leads to the growth of disconnected, island-like structures. The deposition rate is found to influence coalescence dynamics during the early stages of film growth, allowing for the tuning of film microstructure from a more compact, island-like morphology to a more porous structure. The percolation threshold shifts accordingly from 24 nm to 3 nm film thickness. Upon completion of the percolation phase, film resistivity settles at values 2–3 orders of magnitude larger than that of bulk Sn, attributed to the nanogranular nature of cluster-assembled films. During the “3D conduction” phase, resistivity exhibits an increasing trend with thickness following a power law with an exponent value of 0.76–0.78. This behavior is attributed to the decrease in the density of interconnections between particles in the topmost layer during film growth, consistent with expectations in ballistic growth processes.

中文翻译：

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聚结和弹道生长对簇组装纳米结构锡膜原位导电的作用


通过超音速束束沉积组装的纳米结构锡薄膜的电导率在薄膜生长过程中进行了原位研究。 Sn 纳米粒子的动能与 Sn 的低熔点相结合，促进聚结现象，从而能够研究它们对薄膜形态和渗滤阈值的影响。厚度远大于锡纳米粒子尺寸的渗透阈值表明聚结导致不连续的岛状结构的生长。研究发现沉积速率会影响薄膜生长早期阶段的聚结动力学，从而可以将薄膜微观结构从更紧凑的岛状形态调整为更多孔的结构。渗透阈值相应地从 24 nm 薄膜厚度变为 3 nm。渗透阶段完成后，薄膜电阻率稳定在比块状锡大 2-3 个数量级的值，这归因于簇组装薄膜的纳米颗粒性质。在“3D传导”阶段，电阻率随厚度呈现增加趋势，遵循幂律，指数值为0.76-0.78。这种行为归因于薄膜生长过程中最顶层颗粒之间互连密度的降低，这与弹道生长过程的预期一致。