Monolayer InSe photodetector with strong anisotropy and surface-bound excitons

The in-plane anisotropy of monolayer InSe plays a critical role in the application of photodetectors. In this work, through nonequilibrium Green's function density functional theory (NEGF-DFT) and time-dependent density functional theory (TD-DFT) calculations, we investigated the anisotropic quantum transport in darkness and under linearly polarized light, and explored the role of surface-bound excitons in the anisotropic photocurrent. The anisotropic dark quantum transport is attributed to different potential barriers in the zigzag and armchair orientations (Id-zig/Id-arm = 1.2 x 10(2)). Linearly polarized photocurrent calculations show that the extinction ratio reaches a maximum value of 105.67. Moreover, surface-bound exciton calculations via TD-DFT revealed that the strong anisotropic photocurrent derives from surface-bound excitons generated in the In 5p(z), Se 4p(z), and Se 4d(z)(2) orbitals. InSe shows tremendous potential for use in field-effect transistors, flexible nano- and optoelectronics, and polarized light devices.

Automated summary

Through NEGF-DFT and TD-DFT calculations, this work investigated the anisotropic quantum transport of monolayer InSe in darkness and under linearly polarized light, revealing different potential barriers in different crystal orientations. The study found that InSe has great potential for application in photodetectors due to its anisotropic properties.