High-performance solar-blind UV photodetector based on Ti3C2Tx MXene/α-Ga2O3 heterojunction

Abstract

The integration of two-dimensional MXenes with ultrawide bandgap semiconductors presents a novel pathway for high-performance optoelectronics. However, the coupling of Ti3C2Tx with the corundum metastable α-phase of gallium oxide (α-Ga2O3) with wider bandgap than conventional β-phase remains largely unexplored. In this work, we demonstrate a high-sensitivity solar-blind ultraviolet photodetector based on a Ti3C2Tx MXene/α-Ga2O3 heterojunction, fabricated via mist chemical vapor deposition (mist-CVD) and spray-coating techniques. The resulting device exhibits superior optoelectronic performance, achieving a remarkably high photoresponsivity of 31.1 mA/W and an ultralow dark current of 0.41 pA under 254 nm illumination. This enhanced performance is attributed to the formation of high-quality Schottky junction at the MXene and α-Ga2O3 interface, where a work function difference creates a built-in electric field that facilitates efficient carrier separations. Notably, the responsivity of this architecture surpasses that of state-of-the-art α-Ga2O3-based photodetectors, establishing the Ti3C2Tx/α-Ga2O3 heterostructure as a promising candidate for next-generation, low-power deep-UV sensing applications.