Broadband MnSb2Te4 Photodetector from Visible to Terahertz.

Abstract

Photodetectors capable of capturing optical information across multiple spectral regimes are essential for applications in imaging, remote sensing, communication, and biomedicine. However, the development of high-performance ultrabroadband detectors remains challenging due to the wavelength selectivity of photoelectric detectors and the slow response of thermal detectors. Here, we report a highly sensitive MnSb2Te4-based photodetector with a subwavelength metal-semiconductor-metal architecture, enabling ultrabroadband detection spanning visible, infrared, millimeter-wave, and terahertz (THz) bands. The device operates via a dual-mechanism framework, combining interband photogeneration in the visible-infrared region and the electromagnetic-induced well effect in the THz band. In the visible-infrared range, the device exhibits a noise equivalent power (NEP) of 51 pW Hz-1/2 and a fast response time of ∼31 μs. Remarkably, in the millimeter-wave to THz region, it achieves a high voltage responsivity of 4.08 × 107 V W-1, an ultrafast response time of ∼714 ns, and an ultralow NEP of 1.89 × 10-3 pW Hz-1/2 at room temperature. In addition, the device demonstrates strong polarization sensitivity with a dichroic ratio of 117. The superior performance is further validated by high-resolution THz transmission imaging and reliable optical communication based on ASCII-encoded signal transmission, as well as long-term operational stability under room temperature. These results establish MnSb2Te4 as a promising platform for ultrabroadband photodetection and provide new insights into electromagnetic-field-driven detection mechanisms, opening new opportunities for applications in THz imaging, high-speed sensing, and next-generation optoelectronic systems.