Self-powered MXene/GaN van der Waals Schottky ultraviolet photodetectors with exceptional responsivity and stability

High-responsivity and energy-saving ultraviolet photodetectors become crucial components for modern optoelectronic information sensing and communication systems. This study presents an advanced self-powered MXene/GaN Schottky ultraviolet photodetector that features a high-quality van der Waals interface to enhance photoresponsivity. The photodetector exhibits a high responsivity of 681.6 mA W−1 and a significant detectivity of 7.65 × 1013 Jones at zero bias. In a self-powered mode, the detector can operate robustly even under dim illumination (0.15 μW cm−2) due to the excellent Schottky contact and low amount of defect states at the MXene/GaN interface, which presents a strong intrinsic electric field. The photodetector has a high ultraviolet/visible rejection ratio (R360 nm/R400 nm) of 3.9 × 103 and a signal to noise ratio (SNR) of 2.4 × 105, which enable discrimination against visible light interference in real-world scenarios. We also demonstrated that the photodetectors worked well as ultraviolet signal receivers in an optical information communication system to accurately recognize pulsed signals transmitted from an ultraviolet light-emitting diode. These findings imply the great potential of van der Waals Schottky junctions between 2D MXenes and III-nitrides for high-performance photodetection and sensing in many integrated optoelectronic platforms.