A self-powered ultraviolet photodetector with van der Waals Schottky junction based on TiO 2 nanorod arrays/Au-modulated V 2 CT x MXene

A self-powered ultraviolet photodetector (UV PD) with van der Waals (vdW) Schottky junction based on TiO 2 nanorod arrays/Au-modulated V 2 CT x MXene is reported. The Schottky junction enables the device to operate in self-powered mode. The dangling bond-free surface of V 2 CT x MXene reduces the charge recombination at the junction interface. Meanwhile, V 2 CT x MXene, with the work function (WF) increasing to 5.35 eV, forms a hole transport layer by contacting with Au electrode, which facilitates the carrier extraction. The electron lifetime in the device has prolonged to 8.95 mu s. As a result, the responsivity and detectivity of the PD have achieved 28 mA/W and 1.2 x 10 11 cm Hz 1/2 /W (340 nm, 65 mW/cm 2 , 0 V), respectively. In addition, the presence of the Au electrode prevents the vanadium from coming into contact with oxygen and oxidizing, preserving the properties of the V 2 CT x films. After 180 days of exposure to the atmosphere, the device performance remained at a particularly high level, indicating enhanced durability. This work points out an effective approach to modulate the properties of V 2 CT x to obtain the high performance and stability of the UV PD.(c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.