Xue Zhaohang, Fan Zipu, Liao Xin, Li Yaolong, Qin Yulu, Zhang Guanyu, Song Xiaoming, Liao Zhi-Min, Sun Dong, Lu Guowei, Gong Qihuang
State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China.
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
Nano Lett. 2022 Nov 9;22(21):8728-8734. doi: 10.1021/acs.nanolett.2c03574. Epub 2022 Oct 31.
The artificial engineering of photoresponse is crucial for optoelectronic applications, especially for photodetectors. Here, we designed and fabricated a metasurface on a semimetallic CdAs nanoplate to improve its thermoelectric photoresponse. The metasurface can enhance light absorption, resulting in a temperature gradient. This temperature gradient can contribute to thermoelectric photoresponse through the photothermoelectric effect. Furthermore, power-dependent measurements showed a linearly dependent photoresponse of the CdAs metasurface device, indicating a second-order photocurrent response. Wavelength-dependent measurements showed that the metasurface can efficiently separate photoexcited carriers in the broadband range of 488 nm to 4 μm. The photoresponse near the metasurface boundaries exhibits a responsivity of ∼1 mA/W, which is higher than that near the electrode junctions. Moreover, the designed metasurface device provided an anisotropic polarization-dependent photoresponse rather than the isotropic photoresponse of the original CdAs device. This study demonstrates that metasurfaces have excellent potential for artificial controllable photothermoelectric photoresponse of various semimetallic materials.
光响应的人工工程对于光电子应用至关重要，尤其是对于光电探测器。在此，我们在半金属CdAs纳米板上设计并制造了一种超表面，以改善其热电光响应。该超表面可以增强光吸收，从而产生温度梯度。这种温度梯度可通过光热效应促进热电光响应。此外，功率相关测量表明，CdAs超表面器件的光响应呈线性相关，表明存在二阶光电流响应。波长相关测量表明，该超表面能够在488 nm至4μm的宽带范围内有效分离光激发载流子。超表面边界附近的光响应表现出约1 mA/W的响应度，高于电极结附近的响应度。此外，所设计的超表面器件提供了各向异性的偏振相关光响应，而不是原始CdAs器件的各向同性光响应。这项研究表明，超表面在各种半金属材料的人工可控光热电光响应方面具有优异的潜力。
