MXene–TMD heterostructure photodetectors: engineering the Ti3C2/SnS2 interface for high-speed visible light detection

Abstract

Two-dimensional (2D) materials with engineered heterojunctions offer exciting opportunities for next-generation optoelectronic devices. However, achieving high-speed and ambient-stable photodetectors remains challenging. Here, we report a novel heterostructure photodetector based on p-type Ti₃C₂ MXene decorated on vertically aligned n-type SnS₂ nanosheets grown via chemical vapor deposition. This Ti₃C₂/SnS₂ hybrid structure forms a nanoscale p–n junction network with built-in electric fields that significantly enhance photocarrier separation and suppress recombination. The resulting device operates without gate bias and demonstrates a responsivity of 1.34 A W⁻¹, a detectivity of 9.91 × 10¹¹ Jones, and an ultrafast response time of 0.15 ms under visible light illumination. Electrochemical impedance analysis confirms efficient interfacial charge transfer, while the device maintains stable operation over 300 cycles and even after prolonged ambient exposure, highlighting excellent environmental robustness. Comparative analysis with the existing TMD and MXene-based photodetectors establishes the superiority of our approach in simultaneously achieving high speed, sensitivity, and stability. This work offers a scalable platform for developing high-performance 2D material heterojunction devices and sets a new benchmark for MXene-integrated optoelectronics.