  Low-dimensional Si-based semiconductors are unique materials that can both
match well with the Si-based electronics and satisfy the demand of
miniaturization in modern industry. Owing to the lack of such materials, many
researchers put their efforts into this field. In this work, employing a swarm
structure search method and density functional theory, we theoretically predict
two-dimensional atomically thin mononitrides SiN and GeN, both of which present
semiconducting nature. Furthermore study shows that SiN and GeN behave as
indirect band gap semiconductors with the gap of 1.75 and 1.20 eV,
respectively. The ab initio molecular dynamics calculation tells that both two
mononitrides can exist stably even at extremely high temperature of 2000 K.
Notably, electron mobilities are evaluated as 0.888x$10^3$ $cm^2V^{-1}s^{-1}$
and 0.413x$10^3$ $cm^2V^{-1}s^{-1}$ for SiN and GeN, respectively. The present
work expands the family of low-dimensional Si-based semiconductors.

Materials Science