Abstract：
Electronic devices continue to shrink in size while increasing in performance, making excess heat dissipation challenging. Traditional thermal interface materials (TIMs) such as thermal grease and pads face limitations in thermal conductivity and stability, particularly as devices scale down. Carbon nanotubes (CNTs) have emerged as promising candidates for TIMs because of their exceptional thermal conductivity and mechanical properties. However, the thermal conductivity of CNT films decreases when integrated into devices due to defects and bundling effects. This study employs a novel cross-sectional approach combining high-vacuum scanning thermal microscopy (SThM) with beam-exit cross-sectional polishing (BEXP) to investigate the nanoscale morphology and thermal properties of vertically aligned CNT bundles at low and room temperatures. Using appropriate thermal transport models, we extracted effective thermal conductivities of the vertically aligned nanotubes and obtained 4 W m-1 K-1 at 200 K and 37 W m-1 K-1 at 300 K. Additionally, non-negligible lateral thermal conductance between CNT bundles suggests more complex heat transfer mechanisms in these structures. These findings provide unique insights into nanoscale thermal transport in CNT bundles, which is crucial for optimizing novel thermal management strategies.
摘要：
电子设备的尺寸不断缩小，同时性能不断提高，使多余的散热具有挑战性。传统的热界面材料（TIM），如热脂和垫面临的限制，在导热性和稳定性，特别是当设备按比例缩小时。碳纳米管（CNT）由于其优异的导热性和机械性能而成为有希望的TIM候选物。然而,当CNT膜集成到器件中时,由于缺陷和捆扎效应,其热导率降低。本研究采用了一种新颖的横截面方法，将高真空扫描热显微镜（SThM）与光束出口横截面抛光（BEXP）相结合，以研究在低温和室温下垂直排列的CNT束的纳米级形态和热性能。使用适当的热传输模型，我们提取了垂直排列纳米管的有效热导率，并在200K下获得了4Wm-1K-1，在300K下获得了37Wm-1K-1。此外，CNT束之间不可忽视的横向热传导表明这些结构中更复杂的传热机制。这些发现为碳纳米管束中的纳米级热传输提供了独特的见解，这对于优化新的热管理策略至关重要。
