Computational Screening of Highly Stable Semiconducting MXenes with Ultrahigh Carrier Mobilities for Optoelectronic Applications

Two-dimensional (2D) transition metal carbides and nitrides known as MXenes are a new family of 2D materials. Most of the previous studies mainly focus on the metallic MXenes, there are few studies on semiconducting MXenes. Based on first-principles calculations within density functional theory, 480 ground-state structures including 444 metals and 36 semiconductors have been screened from 2256 MXenes using the energy and electronic parameters as the descriptors. The bandgap, carrier mobility, and optical absorption of the semiconducting MXenes show a strong dependence on the surface functional groups. By tuning the surface functional groups, the bandgaps can be changed from 0.2 to 3 eV. Moreover, the semiconducting MXenes exhibit high carrier mobilities up to 10(4) cm(2 )v(-1)s(-1) and high optical absorption coefficients (>10(5) cm(-1)). This work demonstrates that Sc-based and Y-based MXenes present high stability, moderate bandgaps, ultrahigh carrier mobility, and high optical absorption, which make them large potential for electronics, optoelectronics, and photocatalysts.

Automated summary

MXenes are a new family of two-dimensional transition metal carbides and nitrides. Previous studies mainly focused on metallic MXenes, with few studies on semiconducting MXenes. By using first-principles calculations, researchers screened 480 different ground-state structures of MXenes, including 444 metals and 36 semiconductors. It was found that the bandgap, carrier mobility, and optical absorption of semiconducting MXenes strongly depend on the surface functional groups. By tuning the surface functional groups, the bandgaps of semiconducting MXenes can be varied from 0.2 to 3 eV. The semiconducting MXenes also exhibited high carrier mobilities up to 10(4) cm(2 )v(-1)s(-1) and high optical absorption coefficients (>10(5) cm(-1)). This study demonstrates the potential of Sc-based and Y-based MXenes for applications in electronics, optoelectronics, and photocatalysis.