Diverse carrier mobility of monolayer BNC _x : a combined density functional theory and Boltzmann transport theory...

BNC _x monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNC _x (x  =  1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC₂-1 is a material with very small band gap (0.02 eV) among all the structures while other BNC _x monolayers are semiconductors with band gap ranging from 0.51 eV to 1.32 eV. The carrier mobility of BNC _x varies considerably from tens to millions of cm² V^-1 s^-1. For BNC₂-1, the hole mobility and electron mobility along both x and y directions can reach 10⁵ orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNC _x monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC₄, its hole mobility along the y direction and electron mobility along the x direction unexpectedly reach 10⁶ orders of magnitude, even higher than that of graphene. Our findings suggest that BNC _x layered materials with the proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices.