Graphene-like quaternary compound SiBCN: A new wide direct band gap semiconductor predicted by a first-principles study

Due to the lack of two-dimensional silicon-based semiconductors and the fact that most of the components and devices are generated on single-crystal silicon or silicon-based substrates in modern industry, designing two-dimensional silicon-based semiconductors is highly desired. With the combination of a swarm structure search method and density functional theory in this work, a quaternary compound SiBCN with graphene-like structure is found and displays a wide direct band gap. The band gap is of ${\sim}2.63\ \text{eV}$ which is just between ∼2.20 and ${\sim}3.39\ \text{eV}$ of the highlighted semiconductors SiC and GaN. Notably, the following calculation reveals that SiBCN possesses high carrier mobility with ${\sim}5.14\times10^{3}$ and ${\sim}13.07\times10^{3}\ \text{cm}^{2}~\text{V}^{-1}~\text{s}^{-1}$ for electron and hole, respectively. Furthermore, the ab initio molecular dynamics simulations also show that the graphene-like structure of SiBCN can be well kept even at an extremely high temperature of 2000 K. The present work tells that designing multicomponent silicides may be a practicable way to search for new silicon-based low-dimensional semiconductors which can match well with the previous Si-based substrates.