Self-Driven β-Ga2O3 Solar-Blind Deep-Ultraviolet Photodetectors With Asymmetric MXene Electrodes

Here, a $\beta $ -Ga2O3 solar-blind deep-ultraviolet (DUV) photodetector operating in self-driven mode is designed. MXene films with diverse work functions enabled by different doping are drop-coated at opposite ends of a $\beta $ -Ga2O3 microflake to serve as asymmetric electrodes. The different work functions bring about a strong built-in electric field, rendering a pronounced photovoltaic (PV) effect. As a consequence, the light detector reaches a large Ilight/ ${I} _{\text {dark}}$ ratio of $10^{{3}}$ , a low dark current of sub-pA, a decent responsivity of 9.81 mA/W, a respectable specific detectivity of $10^{{11}}$ Jones, and a fast response speed of 10.2/17.7 ms, along with good operational stability, at zero bias, upon 254 nm light. The DUV/ultraviolet rejection ratio can attain $10^{{3}}$ . A flexible device also holds robust durability at various bending states. The study provides a viable route for constructing efficient DUV light detectors and is also helpful for developing MXene-based optoelectronic devices.