Although diamond has the highest known room temperature thermal conductivity, k ～ 2200 W/m K, highly sp~3 amorphous carbon films have k < 15 W/mK. We carry out an integrated experimental and simulation study of thermal transport in ultrananocrystalline diamond (UNCD) films. The experiments show that UNCD films with a grain size of 3-5 nm have thermal conductivities as high as k = 12W/mK at room temperature, comparable with that of the most conductive amorphous diamond films. This value corresponds to a grain boundary (Kapitza) conductance greater than 3000 MW/m~2 K, which is ten times larger than that previously seen in any material. Our simulations of both UNCD and individual diamond grain boundaries yield values for the grain boundary conductance consistent with the experimentally obtained value, leading us to conclude that thermal transport in UNCD is controlled by the intrinsic properties of the grain boundaries.
展开▼
机译：尽管金刚石具有最高的室温热导率，k〜2200 W / m K，但高度sp〜3的非晶碳膜的k <15 W / mK。我们进行了超纳米晶金刚石（UNCD）薄膜热传输的综合实验和模拟研究。实验表明，晶粒尺寸为3-5 nm的UNCD膜在室温下的导热率高达k = 12W / mK，可与大多数导电的非晶金刚石膜相媲美。该值对应于大于3000 MW / m〜2 K的晶界（Kapitza）电导，这是以前在任何材料中看到的电导的十倍。我们对UNCD和单个金刚石晶界的模拟得出的晶界电导值与实验获得的值一致，这使我们得出结论，UNCD中的热传输受晶界的内在特性控制。
展开▼
