MXene-GaN van der Waals Heterostructures for High-Speed Self-Driven Photodetectors and Light-Emitting Diodes

Due to their excellent electrical conductivity, high transmittance, and adjustable work function, 2D transition-metal carbides and nitrides have shown great promise in optoelectronic applications, especially in MXene-semiconductor devices. In this work, Ti3C2TX/(n/p)-GaN van der Waals heterostructures are fabricated and studied. The Ti3C2TX/(n/p)-GaN Schottky junctions are confirmed by ultraviolet photoelectron spectroscopy (UPS) with a work function approximate to 4.2 eV of Ti3C2TX. Based on the Ti3C2TX/(n/p)-GaN Schottky junctions, high-speed photodetectors and stable orange light emitting diodes (LEDs) are fabricated. The Ti3C2TX/n-GaN heterostructure photodetector shows a short rise time (60 ms) and decay time (20 ms), a high responsivity (44.3 mA W-1) and on/off ratio (approximate to 11300) under a light source of 365 nm wavelength and 96.9 mu W cm(-2) power density. And the Ti3C2TX/p-GaN heterostructure LED remains a stable orange light emission under bias voltage from 4 to 22 V. The chromaticity coordinates and color temperature of EL spectrum under 22 V are further calculated to be 0.4541, 0.4432, and 2953 K, respectively. The authors believe that this work provides fundamental insight into the applications of MXene in optoelectronic devices.

Automated summary

2D transition-metal carbides and nitrides, with their excellent electrical conductivity and adjustable work function, show great promise in optoelectronic applications, particularly in MXene-semiconductor devices. In this work, Ti3C2TX/(n/p)-GaN van der Waals heterostructures were successfully fabricated and studied, leading to the development of high-speed photodetectors and stable orange light emitting diodes (LEDs). The Ti3C2TX showed a work function approximate to 4.2 eV and exhibited superior performance in terms of responsivity, on/off ratio, and stability compared to traditional materials.