Abstract
The polarization of light can provide abundant information regarding the polarization degree,phase shift,and Jones vector,which is important in light communication,environmental scanning,quality inspection,etc.Recently,two-dimensional(2D)semiconductors have provided an ideal platform for de-tecting polarized light due to their remarkable and tunable linear dichroism(LD).However,the physical mechanism of the in-plane LD in 2D semiconductors has not been systematically investigated,limiting the further exploration of the 2D anisotropic semiconductors and the directionality of experiments on polariza-tion photodetection.In this study,the in-plane LD of 100 types of 2D semiconductors composed of main group elements is investigated via first-principles theory combined with the decision tree algorithm and ex-perimental measurement.The in-plane asymmetry of the lattice and band edge wavefunctions are the main origins of the in-plane LD.2D semiconductors with in-plane orthorhombic and monoclinic lattices tend to have considerable in-plane LD,while their hexagonal counterparts are optically isotropic.Specifically,or-thorhombic 2D semiconductors possess larger in-plane LD because their intrinsic mirror planes in the lattice induce in-plane parity of the wavefunctions at the band edges.The decision tree algorithm further reveals that in-plane LD is also related to the difference for the a and b lattice constants and the electronegativity difference between the cation and anion.In addition,heterostructures formed from these 2D semiconductors exhibit high light absorption,strong in-plane LD,and various types of band alignment.The result of our study can promote the application and development of 2D semiconductors in polarization optoelectronics.
维普
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