Fabrication of high-responsivity FET photodetector with Ti₃C₂Cl₂ MXene irradiated with 100 keV N ions

MXene has attracted intense attention in optoelectronic photodetectors due to its outstanding electrical conductivity and tunable electronic properties. By using the Ti₃C₂Cl₂ MXene irradiated with 100 keV N ions, a high-performance field-effect transistor (FET) photodetector was achieved and exhibited broadband photoresponse across the ultraviolet–visible–near infrared ray (UV–Vis–NIR) range. The responsivities of these FET photodetectors were as high as 5.3 × 10⁴, 8.5 × 10⁵, 3.3 × 10⁴, and 2.8 × 10⁵ A/W under 360, 550, 750, and 1060 nm light illumination, respectively, which are approximately two orders of magnitude higher than the other MXene-based photodetectors. The remarkable performance of the Ti₃C₂Cl₂ FET photodetector is attributed to synergistic effect of band gap and photoconductive gain. Besides, the ion fluence has significant influence on the photoresponse of the Ti₃C₂Cl₂ FET photodetector, and there exists an optimized ion fluence to obtain the highest responsivity. These findings highlight a controllable strategy for introducing band gap in MXenes and pave the way for their application in next-generation optoelectronic devices.