Ga₂O₃–MXene Nanowire Networks with Enhanced Responsivity for Deep-UV Photodetection

Ga 2 O 3 is a promising semiconductor for solar-blind (200–280 nm) photodetectors. Two-dimensional (2D) MXenes have been widely applied in the optoelectronic area owing to their high conductivity and large specific surface area. The few-layered Ti 3 C 2 T x (Ti 3 C 2 T x -few) exhibits elevated properties compared with multilayered Ti 3 C 2 T x . Herein, we innovatively adopt a hydrothermal method to prepare Ti 3 C 2 T x -few. A Ga 2 O 3 –Ti 3 C 2 T x 3D network heterojunction is fabricated by van der Waals interaction between one-dimensional (1D) nanowires and 2D nanosheets using the light trapping effect at the interface of the heterostructure. The van der Waals force between Ga 2 O 3 and Ti 3 C 2 T x -few enhances the contact for the transfer of photoelectrons. The optimal Ga 2 O 3 –5Ti 3 C 2 T x exhibits enhanced responsivity (140.57 mA W –1 ), defectivity (4.87 × 10 12 Jones), and external quantum efficiency (68.66%), which are 6.67, 3.20, and 6.68 times higher than that of pure Ga 2 O 3 nanowires under deep-ultraviolet light (254 nm). The improved properties of Ga 2 O 3 – x Ti 3 C 2 T x heterostructure are attributed to the high conductivity of Ti 3 C 2 T x -few, enhanced separation of photogenerated electrons and holes, decreased Schottky barrier height, enlarged depletion region, increased UV light absorption, and enhanced contact via van der Waals force between Ga 2 O 3 and Ti 3 C 2 T x . In conclusion, the Ga 2 O 3 –Ti 3 C 2 T x heterojunction extends the application of Ti 3 C 2 T x -few and provides a new tactic to improve the performance of the Ga 2 O 3 -based photodetector.