An ultra‐broadband terahertz (THz) emitter covering a wide range of frequencies from 0.1 to 10 THz is highly desired for spectroscopy applications. So far, spintronic THz emitters have been proven as one class of efficient THz sources with a broadband spectrum while the performance in the lower THz frequency range (0.1–0.5 THz) limits its applications. In this work, a novel concept of a current‐enhanced broad spectrum from spintronic THz emitters combined with semiconductor materials is demonstrated. A 2–3 order enhancement of the THz signals in a lower THz frequency range (0.1–0.5 THz) is observed, in addition to a comparable performance at higher frequencies from this hybrid emitter. With a bias current, there is a photoconduction contribution from semiconductor materials, which can be constructively interfered with the THz signals generated from the magnetic heterostructures driven by the inverse spin Hall effect (ISHE). These findings push forward the utilization of metallic heterostructure‐based THz emitters on the ultra‐broadband THz emission spectroscopy.

中文翻译：

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自旋电子器件的电流增强型宽带太赫兹发射

光谱应用非常需要覆盖0.1至10 THz频率范围的超宽带太赫兹（THz）发射器。到目前为止，自旋电子太赫兹发射器已被证明是具有宽带频谱的一类有效太赫兹源，而在较低太赫兹频率范围（0.1–0.5太赫兹）中的性能限制了其应用。在这项工作中，展示了自旋电子太赫兹发射器与半导体材料组合而成的电流增强型广谱的新颖概念。观察到在较低的THz频率范围（0.1–0.5 THz）内，THz信号增强了2–3阶，此外，该混合发射器在更高的频率下具有可比的性能。借助偏置电流，半导体材料会产生光导作用，它可能会受到反自旋霍尔效应（ISHE）驱动的磁异质结构产生的THz信号的建设性干扰。这些发现推动了基于金属异质结构的太赫兹发射器在超宽带太赫兹发射光谱学上的应用。