JST-ERATO, Itami Molecular Nanocarbon Project, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.
Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.
Nat Commun. 2018 Aug 7;9(1):3144. doi: 10.1038/s41467-018-05598-3.
Thermal radiation is the most primitive light emission phenomenon of materials. Broadband radiation from red-hot materials is well known as the kick-starter phenomenon of modern quantum physics in the early twentieth century; even nowadays, its artificial control plays a central role in modern science and technology. Herein, we report the fundamental thermal radiation properties of intrinsic one-dimensional semiconductors and metals, which have not been elucidated because of significant technical challenges. We observed narrow-band near-infrared radiation from semiconducting single-walled carbon nanotubes at 1000-2000 K in contrast to its broadband metallic counterpart. We confirm that the ultra-narrow-band radiation is enabled by the thermal generation of excitons that are hydrogen-like neutral exotic atoms comprising mutually bound electrons and holes. Our findings uncover the robust quantum correlations in intrinsic one-dimensional semiconductors even at 2000 K; additionally, the findings provide an opportunity for excitonic optothermal engineering toward the realization of efficient thermophotovoltaic energy harvesting.
热辐射是材料最原始的发光现象。在 20 世纪初，宽带辐射的炽热材料是现代量子物理学的启动现象；即使在今天，其人工控制在现代科学技术中也起着核心作用。在此，我们报告了内在一维半导体和金属的基本热辐射特性，由于存在重大技术挑战，这些特性尚未得到阐明。我们观察到在 1000-2000 K 时，半导体单壁碳纳米管发出窄带近红外辐射，而其金属对应物则是宽带辐射。我们证实，这种超窄带辐射是由热激子产生的，激子是由相互束缚的电子和空穴组成的类氢中性奇异原子。我们的发现揭示了即使在 2000 K 时，内在一维半导体中也存在稳健的量子相关性；此外，这些发现为实现高效热光伏能量收集的激子光热工程提供了机会。
