Silicon on a graphene nanosheet with triangle- and dot-shape: Electronic structure, specific heat, and thermal conductivity from first-principle calculations

TL;DR

This study uses first-principles calculations to explore how different silicon doping shapes in graphene nanosheets affect their electronic properties, specific heat, and thermal conductivity, with implications for photovoltaic applications.

Contribution

It reveals how triangular and dot-shaped silicon doping configurations uniquely modify graphene's electronic structure and thermal properties, providing insights for device optimization.

Findings

Triangular silicon doping opens a band gap, transforming graphene into a semiconductor.

Dot-shaped silicon doping maintains metallic behavior with increased density of states.

Doping configurations influence specific heat and thermal conductivity, affecting device performance.

Abstract

The electronic structure, specific heat, and thermal conductivity of silicon embedded in a monolayer graphene nanosheet are studied using Density Functional Theory. Two different shapes of the substitutional Si doping in the graphene are studied, a triangular and a dot shape. The silicon doping of a graphene nanosheet, with the silicon atoms arranged in a triangular configuration in ortho- and para-positions, opens up a band gap transforming the sheet to a semiconducting material. The opening of the band gap is caused by the presence of the repulsion force between the silicon and carbon atoms decreasing the density of states around the Fermi energy. Consequently, the specific heat and the thermal conductivity of the system are suppressed. For graphene nanosheet doped with a dot-like configuration of silicon atoms, at the ortho-, meta-, and para-positions, the valence band crosses the Fermi level. This doping configuration increases the density of state at the Fermi level, but mobile charge are delocalized and diminished around the silicon atoms. As a result, the specific heat and the thermal conductivity are enhanced. Silicon substitutionally doped graphene nanosheets may be beneficial for photovoltaics and can further improve solar cell devices by controlling the geometrical configuration of the underlying atomic systems.