Ferro-Pyro-Phototronic Effect Enhanced Self-Powered UV Photodetectors Based on BaTiO₃@MXene/4H-SiC Heterojunction

Ferroelectric materials, known for their superior spontaneous polarization and pyroelectric and photovoltaic effects, offer a promising avenue for fabricating high-performance optoelectronic devices. Herein, we report an ultraviolet (UV) photodetector (PDs) based on BaTiO3@MXene/4H-SiC heterostructure, with its photosensitive properties significantly boosted by the ferro-pyro-phototronic effect. In the detector, the incorporation of MXene nanosheets boosts the spontaneous ferroelectric polarization of BaTiO3 nanocrystals, thereby strengthening the built-in electric field at the BaTiO3/4H-SiC heterojunction. The resulted BaTiO3@MXene/4H-SiC heterostructure can work in a self-biasing manner, with robust performances, including responsivity (∼187.74 mA/W), specific detectivity (∼6.52 × 1013 Jones), external quantum efficiency (∼75.07%), response/recovery time (∼74.3/122.7 μs) upon 310 nm light irradiation. Particularly, the superlinear increase of the photocurrent, which results from the hot-carrier multiplication in MXene nanosheets, allows the device to produce additional photocurrent under ultraviolet illumination. Theoretical analysis confirms that the surface modification of MXene nanosheets can effectively alter the length of the Ti–O bonds on BaTiO3 nanocrystal surfaces, thus enhancing their spontaneous ferroelectric polarization. Being seamlessly integrated into an ultraviolet wireless communication system, the BaTiO3@MXene/4H-SiC self-powered photodetector demonstrates promising application prospects in optoelectronic interconnection circuits. This study provides an optimization strategy for advanced BaTiO3 nanocrystals toward future high-performance electronic and optoelectronic devices in existing applications.