Directly Laser-Patterned TiSe₂–TiO₂ Lateral-Junction for High-Performance Ultraviolet Photodetection

Two-dimensional (2D) ultraviolet (UV) photodetectors have attracted enormous interest due to their potential applications in the wide fields of biology, healthcare, and space science. Here, by applying a focused laser beam for direct patterning, we demonstrate local oxidation in metallic 1T TiSe2 that converts it to rutile TiO2, a wide band gap semiconductor. The formed TiSe2–TiO2 lateral heterojunction can act as a photodetector, exhibiting high responsivity (>180 A/W) in the UV wavelength region. Furthermore, we observe a superlinear photoresponse in such demonstrated photodetector. Our work provides a methodology to build high-performance 2D photodetectors using focused laser irradiation, thus enriching the methods available for developing prototypes of low-dimensional optoelectronic devices in the future.