Interface engineering SnS2/MXene Nb2C self-powered photodetectors with high responsivity and detectivity

Research on two-dimensional (2D) materials and their van der Waals heterostructures (vdWHs) has generated a lot of interest in the fields of electronics and optoelectronics. However, the construction of 2D heterostructures remains a challenge because the most widely used deterministic placement method to perform 2D layer stacking often suffers from erratic control of lattice orientation over lattice orientations. Herein, a new 2D/2D SnS2/MXene Nb2C heterostructure for high-performance photodetectors (PDs) was designed and prepared by using a simple electrostatic assembly process. It was demonstrated that the combination of Nb2C MXene nanosheets (NSs) and SnS2 NSs significantly improved the performance of PDs by enhancing the charge transfer, carrier density, light adsorption, as well as by decreasing band bending edge and charge recombination. The SnS2/Nb2C PDs exhibited remarkable responsivity (102.44 μA/W) and ultrahigh specific detectivity (7.48 × 1012 Jones) at zero external bias under a 365 nm laser at level Ⅳ. Additionally, comprehensive investigations of energy level diagram derived from both experimental measurements and density functional theory calculations provided further insights of such photodetector system. This simple and reliable fabrication strategy opens a new avenue for the large-scale production of low-cost and high-quality MXenes-based heterogeneous bond for next-generation electronic and optoelectronic applications.