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

Ga2O3is 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 Ti3C2Tx (Ti3C2Tx-few) exhibits elevated properties compared with multilayered Ti3C2Tx. Herein, we innovatively adopt a hydrothermal method to prepare Ti3C2Tx-few. A Ga2O3–Ti3C2Tx 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 Ga2O3 and Ti3C2Tx-few enhances the contact for the transfer of photoelectrons. The optimal Ga2O3–5Ti3C2Tx exhibits enhanced responsivity (140.57 mA W–1), defectivity (4.87 × 1012 Jones), and external quantum efficiency (68.66%), which are 6.67, 3.20, and 6.68 times higher than that of pure Ga2O3 nanowires under deep-ultraviolet light (254 nm). The improved properties of Ga2O3–xTi3C2Tx heterostructure are attributed to the high conductivity of Ti3C2Tx-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 Ga2O3 and Ti3C2Tx. In conclusion, the Ga2O3–Ti3C2Tx heterojunction extends the application of Ti3C2Tx-few and provides a new tactic to improve the performance of the Ga2O3-based photodetector.