High-performance Te terahertz detector based on Au nanofilm microcavity

Abstract

In terahertz system, terahertz detector is one of the core devices that directly affect the system’s performance. At present, the development of terahertz detector with high sensitivity, fast response speed, and simple structure for easy integration is still a research hotspot. In this paper, a high-efficiency and low-cost magnetron sputtering method is used to grow large-area Au nanofilm and Weyl semiconductor Te film. The photon absorption of the semiconductor material Te is significantly enhanced by introducing Au nanofilm as an optical resonance cavity in the bottom layer, which is combined with a sub-wavelength-structured grating electrode and the introduction of a localized surface plasmon (LSP) effect, to fabricate a metal-topological semiconductor–metal structure of large-area terahertz detector successfully. The device breaks through the limitation of material bandgap and can achieve high-sensitivity detection of terahertz wave. Under light irradiation at a frequency of 0.1 THz, the responsivity is 4.71 A/W, the noise equivalent power NEP is 15.6 pW Hz^−1/2, and the specific detectivity D* is 7.86 × 10⁹ cm Hz^1/2 W⁻¹. This work provides an effective way to achieve high-sensitivity, large-area detection of terahertz wave.