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arXiv · 1702.01303

High-efficiency spontaneous terahertz emission from electrically-excited plasmons in AlGaN/GaN two-dimensional electron gas

Hua Qin·Yao Yu·Jiandong Sun·Zhongxin Zheng·Yongdan Huang·Xingxin Li·Yu Zhou·Dongmin Wu·Zhipeng Zhang·Cunhong Zeng·Yong Cai·Xiaoyu Zhang·Baoshun Zhang·Xuecou Tu·Gaochao Zhou·Biaobing Jin·Lin Kang·Jian Chen·Peiheng Wu
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Abstract

The advance of terahertz science and technology yet lays wait for the breakthrough in high-efficiency and high-power solid-state terahertz sources applicable at room temperature. Plasmon in two-dimensional electron gas (2DEG) has long been pursued as a type of promising active medium for terahertz emitters. However, a high wall-plug efficiency sufficient for high-power operation has not been achieved. Here we report spontaneous terahertz emission tunable in a frequency range from 0.3 to 2.5 THz through electrical excitation of plasmon or plasmon-polariton modes in a grating-gate coupled AlGaN/GaN 2DEG at 7 K. A wall-plug efficiency ranging from $10^{-6}$ to $10^{-1}$ is found by tuning the energy (4.5 eV to 0.5 eV) of tunneling electrons between the grating gates and the 2DEG. The total emission power, albeit below 15 nW, is already detectable by using a direct terahertz field-effect transistor detector based on the same type of 2DEG. The findings indicate that both high-efficiency and high-power terahertz plasmon-polariton emission could be obtained by a proper injection of tunneling electrons with low energy and high current density.

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Hua Qin, Yao Yu, Jiandong Sun, Zhongxin Zheng, Yongdan Huang, Xingxin Li, Yu Zhou, Dongmin Wu, Zhipeng Zhang, Cunhong Zeng, Yong Cai, Xiaoyu Zhang, Baoshun Zhang, Xuecou Tu, Gaochao Zhou, Biaobing Jin, Lin Kang, Jian Chen, Peiheng Wu. 2017-02-04. High-efficiency spontaneous terahertz emission from electrically-excited plasmons in AlGaN/GaN two-dimensional electron gas. https://arxiv.org/abs/1702.01303

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