Two-dimensional W8S6Se6 monolayers: intrinsic semiconductors with high anisotropic carrier mobility and optoelectronic performance from first-principles.

Two-dimensional (2D) semiconductors hold tremendous promise for the development of next-generation optoelectronics and electronics. Nonetheless, existing 2D semiconductors are plagued by inherently low carrier mobility at ambient temperatures, which restricts their possible applications. In this work, we explore several crystalline phases of W8S6Se6 monolayers, assessing their structural stability and fundamental characteristics through first-principles calculations. Our results demonstrate that all the investigated structures maintain remarkable thermodynamic and mechanical stability. Electronic structure analysis indicates that P6m2, P6mm, P3m1, Cmm2, and C2/m-W8S6Se6 monolayers function as intrinsic semiconductors, exhibiting bandgaps between 1.01 and 1.04 eV, according to the HSE06 functional level. Additionally, these monolayers showcase impressive ductility and exhibit excellent light absorption coefficients of 105 cm-1 across the near-infrared to visible spectrum. Remarkably, they display considerable anisotropic carrier mobility, with electron mobility in the y direction frequently reaching 104 cm2 V-1 s-1. Overall, these innovative W8S6Se6 monolayers not only expand the repertoire of 2D optoelectronic materials but also offer promising avenues for future nanoelectronics and sensors.