Weyl-Semimetal TaIrTe4/Si Nanostructures for Self-Powered Schottky Photodetectors.

Weyl semimetal-based photodetectors have attracted great attention due to their high performance in fast, self-powered, and ultra-broad-band photodetection. However, the inherent large dark current of the semimetal hinders further improvement of their performance. Thus, it is urgent to utilize a van der Waals (vdW) heterojunction strategy to effectively decrease the dark current and separate the carriers. Herein, a vertical Schottky junction photodetector based on Weyl semimetal TaIrTe₄ and n-Si nanostructures has been studied. The junction presents a high photoresponsivity of 910 mA W^–1, a specific detectivity of ∼1.04 × 10¹¹ jones, and a fast response speed of 15.1/18.2 μs under 808 nm irradiation. Furthermore, a stable and reproducible broad-band detection (325–2000 nm) is achieved, due to the efficient NIR light absorption of TaIrTe₄. In particular, the device presents impressive responsivities of 14/1.32/0.45 mA W^–1 under 1310/1550/2000 nm light, respectively. Notably, these excellent performances of the TaIrTe₄/Si nanostructures are superior to those of most of the previously explored 2D materials/Si-based devices and are comparable to those of several commercial silicon photodiode sensors. It is believed that the above results can provide ideas for the research of Weyl semimetals in the application of high-performance nanoscale optoelectronic devices. [ABSTRACT FROM AUTHOR]