MXene-Enhanced Deep Ultraviolet Photovoltaic Performances of Crossed Zn₂GeO₄ Nanowires

The Zn₂GeO₄ crystal is an ideal semiconductor for deep ultraviolet (DUV) detection due to its wide band gap of ∼4.69 eV. To further improve its DUV performance, two-dimensional (2D) MXenes with high electrical conductivity, potentially tunable electronic structure, and nonlinear optical properties were applied on crossed Zn₂GeO₄ nanowire (NW) network materials. The results presented here show that the DUV detectors based on Zn₂GeO₄/MXene hybrid nanostructures exhibited excellent optoelectronic performances with a largest responsivity of 20.43 mA/W and external quantum efficiency (EQE) of 9.9% under 254 nm wavelength light illumination. The excellent optical performance is from the synergistic effect of MXene and Zn₂GeO₄ nanowires. The metallic property of MXene provides a fast electron transport for Zn₂GeO₄/MXene, which leads to a larger photocurrent and a fast photoresponse. The construction of unique semiconductive–conductive networks and large interfaces of Zn₂GeO₄ NWs, MXene layers, and the interfaces between them also promotes photoinduced electron–hole separation in the sample. Considering a large number of members in MXene, this study demonstrates a new strategy applicable for maximizing their applications in deep ultraviolet photodetectors.