A polarization-sensitive, high on/off ratio and self-powered photodetector based on Nb₂CT_xand Nd₂CT_x@MoS₂

MXene two-dimensional materials have been widely used in energy storage, catalysis, sensing and other fields, Nb₂C as a typical two-dimensional MXene material, its exploration in the field of optoelectronics is still in its infancy, especially Nb₂C-based photodetectors are still to be developed. This paper demonstrates that two-dimensional films based on few-layer Nb₂C have a photoelectric response in the wavelength range from visible to near-infrared. We have found that the light response performance can be easily adjusted by controlling the thickness of the spin-coated film, and that Nb₂C photodetectors show great advantages in terms of wide bandwidth, polarization response, high switching ratio, etc. By adjusting the material concentration and sample thickness, the photocurrent can reach up to 330 nA, the switching ratio can reach 410, and the responsivity can reach 8.3 × 10^-4A W^-1. In the polarization characteristic test, an extinction ratio of 7.6 can be obtained. By adjusting the content of that doped MoS₂quantum dot, the dark current can reach 7.6 × 10^-13A, and the switching ratio can reach 3 × 10⁵, which can be increased by 700 times. The above results show that the few-layer Nb₂C nanosheets can be used as optoelectronic detectors in the visible to near-infrared bands, which further broadens the application prospects of two-dimensional MXene.