Zou Yuexin, Pan Hong, Huang Shenyang, Chen Pingping, Yan Hugen, An Zhenghua
Opt Express. 2021 Jan 18;29(2):1244-1250. doi: 10.1364/OE.415232.
With the downscaled device size, electrons in semiconductor electronics are often electrically driven out-of-thermal-equilibrium with hosting lattices for their functionalities. The thereby electrothermal Joule heating to the lattices can be visualized directly by the noncontact infrared radiation thermometry with the hypothetic Planck distribution at a single characteristic temperature. We report here that the infrared emission spectrum from electrically biased GaAs devices deviates obviously from Planck distribution, due to the additional contribution from non-equilibrium hot electrons whose effective temperature reaches much higher than that of the lattice (Te>Tl). The evanescent infrared emission from these hot electrons is out-coupled by a near-field metamaterial grating and is hence made significant to the total far-field emission spectrum. Resonant emission peak has also been observed when the electron hotspots are managed to overlap spatially with the optical hotspots at the grating resonance. Our work opens a new direction to study nonequilibrium dynamics with (non-Planckian) infrared emission spectroscopy and provides important implications into the microscopic energy dissipation and heat management in nanoelectronics.
随着器件尺寸的缩小，半导体电子器件中的电子通常会因功能需求而被电驱动至与宿主晶格处于非热平衡状态。由此产生的晶格电热焦耳热可以通过非接触红外辐射测温法直接观察到，假设在单一特征温度下存在普朗克分布。我们在此报告，由于非平衡热电子的额外贡献，其有效温度远高于晶格温度（Te>Tl），电偏置的GaAs器件发出的红外发射光谱明显偏离普朗克分布。这些热电子的瞬逝红外发射通过近场超材料光栅向外耦合，因此对总的远场发射光谱有显著影响。当电子热点在空间上与光栅共振处的光学热点重叠时，还观察到了共振发射峰。我们的工作为用（非普朗克）红外发射光谱研究非平衡动力学开辟了新方向，并为纳米电子学中的微观能量耗散和热管理提供了重要启示。
