发表机构
Arizona State University（亚利桑那州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用环形微热电偶结在10纳米间隙下观测到高达2600倍的近场热辐射增强，并实现VO2相变调制的可调谐传热，推进了纳米尺度能量输运研究。
AI 中文摘要
近场辐射传热已被理论预测和实验证明，在纳米尺度真空间隙中，通过倏逝表面波耦合，其传热可超过远场黑体极限，但在室温附近，超过100倍的显著增强通常需要亚50纳米的真空间隙。对于具有毫米级样品尺寸的平行板构型，由于固有的晶圆弯曲和污染颗粒，这具有挑战性。球-板构型，其中微球附着在双材料悬臂或微热电偶尖端上，已被用于实验证明低至30纳米间隙的近场辐射传热，但由于复杂传感器制造的挑战、低灵敏度和弱信号，其发展较为滞后。在本工作中，我们通过一种环形微热电偶结克服了这些挑战，该结通过简单的薄膜沉积在玻璃纤维末端制造，实现了高测量精度，具有大的塞贝克系数25微伏/开尔文和热阻8.7×10^6开尔文/瓦。在微热电偶结下方附着二氧化硅微球，我们报告了实验观测到的巨大近场辐射传热超过黑体极限，低至10纳米间隙，石英的增强高达2600倍，掺杂硅的增强高达900倍。在VO2薄膜发射体的相变过程中，实验证明了在15纳米间隙下可调谐近场传热增强高达430倍，减少了64%。实验数据与基于涨落电动力学和Derjaguin近似的严格建模吻合良好，其潜在机制通过能量传输计算得以理解。这些结果将推进纳米尺度间隙能量输运的实验研究和基本理解。
英文摘要
Near-field radiative heat transfer between two objects has been theoretically predicted and experimentally demonstrated to exceed far-field blackbody limit across nanoscale vacuum gap distance enabled by evanescent surface waves coupling, while significant enhancement by more than 100 times usually requires sub-50-nm vacuum gaps around room temperature. This is challenging for parallel-plate configuration with millimeter sample sizes due to intrinsic wafer bow and contaminant particles. Sphere-plate configuration with a microsphere attached to bimaterial cantilevers or micro-thermocouple tips has been used to experimentally demonstrate near-field radiative heat transfer down to 30-nm gaps, but it is much less developed because of the challenges in the sophisticated sensor fabrication, low sensitivity and weak signals. In this work, we overcome these challenges by an annular micro-thermocouple junction fabricated at the end of a glass fiber with straightforward thin-film deposition to achieve high measurement accuracy with large Seebeck coefficient 25 uV/K and thermal resistance 8.7e6 K/W. With a silica microsphere attached underneath the micro-thermocouple junction, we report experimental observation of colossal near-field radiation heat transfer over blackbody limit down to 10-nm gap up to 2600 times with quartz and 900 times with doped silicon. Upon phase transition of VO2 thin film emitter, tunable near-field heat transfer up to 430-fold enhancement is experimentally demonstrated at 15-nm gap with 64% reduction. Experimental data agrees well with rigorous modeling based on fluctuational electrodynamics and Derjaguin approximation, and underlying mechanism is understood by energy transmission calculations. The results will advance the experimental study and fundamental understanding of energy transport at nanoscale gaps.
