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

## TL;DR

This study predicts a new graphene-like quaternary SiBCN compound with a wide direct band gap and high carrier mobility, potentially advancing silicon-based 2D semiconductors for industry applications.

## Contribution

First-principles prediction of a stable, wide-bandgap, graphene-like SiBCN monolayer with high mobility, filling a gap in 2D silicon-based semiconductor research.

## Key findings

- SiBCN has a ~2.63 eV direct band gap.
- High carrier mobility: ~5.14x10^3 cm^2V^-1s^-1 for electrons.
- Structural stability at 2000 K.

## Abstract

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 as expected. The band gap is of ~2.63 eV which is just between ~2.20 and ~3.39 eV of the highlighted semiconductors SiC and GaN. Notably, the further calculation reveals that SiBCN possesses high carrier mobility with ~5.14x10^3 and ~13.07x10^3 cm^2V^-1s^-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 ulticomponent 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.