Metasurface Enabled Photothermoelectric Photoresponse of Semimetal Cd3As2 for Broadband Photodetection

The artificial engineering of photoresponse is crucial for optoelectronic applications, especially for photodetectors. Here, we designed and fabricated a metasurface on a semimetallic Cd3As2 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 Cd3As2 metasurface device, indicating a second-order photo current response. Wavelength-dependent measurements showed that the metasurface can efficiently separate photoexcited carriers in the broadband range of 488 nm to 4 mu m. The photoresponse near the metasurface boundaries exhibits a responsivity of similar to 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 Cd3As2 device. This study demonstrates that metasurfaces have excellent potential for artificial controllable photothermoelectric photoresponse of various semimetallic materials.

Automated summary

The artificial engineering of photoresponse is crucial for optoelectronic applications, and in this study, a metasurface on a semimetallic Cd3As2 nanoplate was designed and fabricated to improve its thermoelectric photoresponse. The metasurface enhanced light absorption and resulted in a temperature gradient, contributing to the thermoelectric photoresponse. The power-dependent and wavelength-dependent measurements confirmed the excellent photoresponse characteristics of the metasurface device, including a linearly dependent photoresponse and efficient separation of photoexcited carriers. The designed metasurface device also demonstrated an anisotropic polarization-dependent photoresponse. This study highlights the potential of metasurfaces in controlling the photoresponse of semimetallic materials.