Observation of ambipolar photoresponse from 2D MoS2/MXene heterostructure

Two-dimensional materials have been demonstrated as promising toolboxes for optoelectronics. Transition metal carbides and nitrides (MXenes), members of an emerging family of two-dimensional materials, have drawn extensive attention in optoelectronics owing to their excellent conductivity and tunable electronic properties. Herein, a photodetector based on the two-dimensional van der Waals heterostructure of Ti3C2Tx MXene and a MoS2 monolayer was constructed to observe the ambipolar photoresponse, which showed a positive photoresponse in the visible spectrum (500-700 nm) and a negative photoresponse at longer wavelengths (700-800 nm). The device exhibited a high negative responsivity of 1.9 A/W and a detectivity of 2.1 x 10(10) Jones under 750 nm light illumination. Detailed experiments demonstrate that the negative photoresponse arises from the heterostructure-induced trap energy level, which confines the excited photoelectrons and leads to an inverse current. This work demonstrates a unique optoelectronic phenomenon in MoS2/MXene heterostructures and provides valuable insights into the development of new photodetection materials.

Automated summary

A photodetector based on the van der Waals heterostructure of Ti3C2Tx MXene and MoS2 monolayer was constructed, showing ambipolar photoresponse with positive response in visible spectrum and negative response at longer wavelengths. The device exhibited high negative responsivity and detectivity under specific light illumination, demonstrating a unique optoelectronic phenomenon in MoS2/MXene heterostructures and providing insights for new photodetection materials.