Near-field radiative heat transfer between parallel structures in the deep subwavelength regime
Near-field radiative heat transfer between parallel structures in the deep subwavelength regime
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DOI：
10.1038/nnano.2016.20
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发表时间：
2016-06-01
影响因子：
38.3
通讯作者：
Lipson, Michal
中科院分区：
文献类型：
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作者：
St-Gelais, Raphael;Zhu, Linxiao;Lipson, Michal
由深亚波长距离分开并受到大的热梯度（>100 K）的平行物体之间的热辐射可以达到非常高的幅度，同时集中在窄的频率分布上。这些独特的特性可以实现热传输控制（1-3）和发电（4-8）的突破性技术（例如，通过精确地以光伏电池的带隙频率辐射热量）。然而，由于难以在纳米级距离上保持大的热梯度同时避免其他传热机制（即传导），因此从未通过实验实现过这种情况下的热传输。在这里，我们展示了近场辐射热传递之间的平行SiC纳米梁在深亚波长制度。梁之间的距离由高精度微机电系统（MEMS）控制。我们利用纳米梁在高拉伸应力下的机械稳定性，以最大限度地减少热屈曲效应，因此即使在大的热梯度下也能控制纳米尺度的分离。我们实现了近两个数量级的热传递的增强相对于远场极限（对应于42 nm的分离），并表明，我们可以保持260 K的温度梯度之间的冷，热表面在类似于100 nm的距离。
Thermal radiation between parallel objects separated by deep subwavelength distances and subject to large thermal gradients (>100 K) can reach very high magnitudes, while being concentrated on a narrow frequency distribution. These unique characteristics could enable breakthrough technologies for thermal transport control(1-3) and electricity generation(4-8) (for example, by radiating heat exactly at the bandgap frequency of a photovoltaic cell). However, thermal transport in this regime has never been achieved experimentally due to the difficulty of maintaining large thermal gradients over nanometre-scale distances while avoiding other heat transfer mechanisms, namely conduction. Here, we show near-field radiative heat transfer between parallel SiC nanobeams in the deep subwavelength regime. The distance between the beams is controlled by a high-precision micro-electromechanical system (MEMS). We exploit the mechanical stability of nanobeams under high tensile stress to minimize thermal buckling effects, therefore keeping control of the nanometre-scale separation even at large thermal gradients. We achieve an enhancement of heat transfer of almost two orders of magnitude with respect to the far-field limit (corresponding to a 42 nm separation) and show that we can maintain a temperature gradient of 260 K between the cold and hot surfaces at similar to 100 nm distance.