We investigate the electrical conductivity and thermal conductivity of polycrystalline gold nanofilms, with thicknesses ranging from 40.5 nm to 115.8 nm, and identify a thickness-dependent electrical conductivity, which can be explained via the Mayadas and Shatzkes (MS) theory. At the same time, a suppressed thermal conductivity is observed, as compared to that found in the bulk material, together with a weak thickness effect. We compare the thermal conductivity of suspended and supported gold films, finding that the supporting substrate can effectively suppress the in-plane thermal conductivity of the polycrystalline gold nanofilms. Our results indicate that grain boundary scattering and substrate scattering can affect electron and phonon transport in polycrystalline metallic systems.

我们研究了厚度从 40.5 nm 到 115.8 nm 的多晶金纳米薄膜的电导率和热导率，并确定了与厚度相关的电导率，这可以通过 Mayadas 和 Shatzkes (MS) 理论来解释。同时，与在块状材料中发现的相比，观察到抑制的热导率以及较弱的厚度效应。我们比较了悬浮和支撑金薄膜的热导率，发现支撑衬底可以有效地抑制多晶金纳米薄膜的面内热导率。我们的结果表明，晶界散射和衬底散射可以影响多晶金属系统中的电子和声子传输。