Artificial control of in-plane anisotropic photoelectricity in monolayer MoS2

Intrinsic linear polarized optics discovered in anisotropic two-dimensional (2D) materials has attracted intense interest for polarization-sensitive optical and optoelectronic applications , such as black phosphorous, ReSe 2 , etc. However, the lack of matured method to synthesize high-quality, large-scale and air-stable 2D materials with anisotropic properties, is still an obstacle for practical applications. Monolayer molybdenum disulfide (MoS 2 ), which exhibits strong direct-band-gap light-harvesting properties, can be grown maturely. But unfortunately, MoS 2 does not show linear dichroism owing to its in-plane isotropic crystalline symmetry. We, herein, for the first time, report on an artificial control of extrinsic linear polarized photoelectric effect in monolayer MoS 2 , by successfully controlling its anisotropic degree of in-plane crystal symmetry via artificially induced uniaxial tensile strain . Strong linear polarization-sensitive photodetection from visible to near-infrared range is realized for monolayer MoS 2 -based device, and the polarization anisotropic ratio can reach up over 2.0 under 4.5% strain. The observation is supported by combination of experiment-theory study on polarized Raman spectrum and optical absorption under gradually applied strains. Our results have demonstrated that the artificial-controlled symmetry reducing of MoS 2 is a promising strategy to achieve high performance polarization photodetection. This method can also be extended to other 2D materials, which potentially opens up a new field to endow isotropic 2D materials with anisotropic functionalities by artificial structure engineering.