Yulu Chen, Xiong Yang, Wulin Tong, Bingbing Wang, Chuansheng Zhang, Haoxing Zhang, Yongshan Hu, Ming Pan, Xiaodong Wang
https://link.springer.com/article/10.1007/s11082-019-1834-8
Terahertz (THz) photodetectors have attracted great attention from scientists worldwide for their application in security checking, biomedical treatment and astronomical observation of remote stars and distant galaxies. As a typical THz detector, extrinsic GaAs based photoconductive detector is facing critical technical bottlenecks in the epitaxial growth of sufficiently thick and high-quality GaAs absorption layer. In this work, a novel THz photoconductive detector based on metamaterial/GaAs/electrode layer hybrid structure was designed and simulated. By setting the periodic split ring resonator (SRR) structure as 88 μm pitch with 8 μm width, the absorption peaks exist at the wavelength of about 142 and 367 μm, which originate from the resonant cavity and the SRR dipole resonance effect, and the novel device shows a significant enhancement compared with the conventional GaAs photoconductive detector. Thus, the necessary thickness of GaAs absorption-layer is largely reduced, and the resonant absorption peak can be modulated by changing the thickness of absorption layer. This work provides a novel device structure which can solve the critical epitaxial growth bottleneck of GaAs photoconductive detector and used for the astronomical observation, security check, etc.
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