Edge-contacted MoTe2-NbS2 heterojunction photodetectors with high-performance, self-powered and stable broadband detection based on optical manipulation preparation

Photodetectors, as fundamental components of modern optoelectronic systems, hold significant potential across various domains including communications, healthcare, and military reconnaissance. Heterojunctions play a crucial role in enhancing carrier separation through interface energy band engineering, thereby enabling high-performance detection. Furthermore, metal–semiconductor edge contacts can further optimize device performance, though conventional fabrication methods are often complex, time-consuming, and risk inducing material damage. We proposed a novel approach for realizing edge contact between 2D semiconductors and metals by using femtosecond laser-driven nanosheets moving on a substrate. MoTe₂ and NbS₂ nanosheets were precisely assembled into edge-contact heterojunction photodetectors by combining dry transfer techniques with optical manipulation. The device exhibited excellent responsivity (2 A/W), specific detectivity (1.36×10⁸ Jones), and quantum efficiency (278%) at 900 nm. Additionally, the photodetectors exhibited fast response times of 30/46 μs, a response bandwidth of 5.4 kHz, making it suitable for high-speed optical signal detection. Significantly, the detectors showed broadband optical response spanning 280–1380 nm, with a stable responsivity maintained between 280 and 1200 nm. The optical manipulation scheme also provides new solutions for the preparation of transverse heterojunction, customized edge-contact structure, and modulation of heterojunction junction area, which injects new momentum for the development of future optoelectronic devices