MnBi2Te4/3D-microstructure hybrid for THz detection

Abstract

Terahertz (THz) detectors are critical for frontier applications such as material characterization, nondestructive testing, and high-speed sensing, demanding ultra-high responsivity, low noise, and room-temperature operability. Conventional detection technologies are hindered by insufficient carrier mobility, weak light–matter interaction, and limited tunability. Herein, we propose a synergistic strategy integrating topological insulator MnBi2Te4 with 3D-printed subwavelength microstructures, enabling enhanced localized surface plasmon resonance and laser-magnetic field co-modulation of carrier behavior. High-quality MnBi2Te4 films were deposited via magnetron sputtering on 3D-printed microstructures fabricated by surface projection micro-stereolithography. Under 12 V bias, the detector achieves a voltage responsivity of 4.5 × 104 V/W (150% enhancement vs pristine device) and a noise-equivalent power of 12.8 pW/Hz1/2 at 0.1 THz with a 445 nm, 40 mW laser. Notably, a low 1/f noise corner frequency of 91 Hz ensures superior signal-to-noise ratio for low-frequency detection. External laser power, magnetic field strength, and THz frequency synergistically modulate the device's performance, providing a novel paradigm for high-performance THz detectors.