Unipolar Barrier Engineering in 1D/2D Hybrid Van der Waals Heterostructures for High-Performance Broadband Polarization-Sensitive Photodetection.

Unipolar barrier architecture has emerged as a transformative design for infrared photodetectors, leveraging selective carrier blocking to suppress dark currents while preserving photocurrent. 1D nanowires with strong optoelectronic/polarization-detection capabilities raise the question of whether their performance can be further enhanced via unipolar barrier engineering. Here, we developed a Bi2S3 nanowire-based unipolar barrier nBn photodetector using a novel dual-process strategy that combines femtosecond laser ablation (for precise nanowire segmentation) and 2D WS2 van der Waals integration (for barrier engineering). This 1D/2D hybrid architecture suppresses dark currents by four orders of magnitude while realizing enhanced broadband polarization-sensitive photoresponse, enabling high photoresponsivity (17.6 A/W), detectivity (2.6 × 1011 cm H1/2 W-1), and robust linearly dichroic ratio (1.6) at near-infrared (980 nm). Our work innovatively adopts unipolar barrier architectures to bridge the anisotropy of 1D nanowires and 2D barrier engineering, significantly enhancing the optoelectronic performance of 1D nanowires and paving the way for their high-potential applications in infrared sensing, polarization detection, and dual-band photodetection.