[Paper Review] Optical and electronic properties of two dimensional graphitic silicon carbide

Xiao Lin, Yang Xu+5 more|arXiv (Cornell University)|May 24, 2012

Graphene research and applications1 references4 citations

TL;DR

This study investigates the optical and electronic properties of few-layer graphitic silicon carbide (GSiC) using density functional theory, revealing that monolayer GSiC exhibits a direct bandgap tunable via in-plane strain, while few-layer GSiC shows an indirect bandgap. The findings position monolayer GSiC as a promising candidate for novel light-emitting diodes due to its unique optoelectronic behavior distinct from graphene and silicene.

ABSTRACT

Optical and electronic properties of two dimensional few layers graphitic silicon carbide (GSiC), in particular monolayer and bilayer, are investigated by density functional theory and found different from that of graphene and silicene. Monolayer GSiC has direct bandgap while few layers exhibit indirect bandgap. The bandgap of monolayer GSiC can be tuned by an in-plane strain. Properties of bilayer GSiC are extremely sensitive to the interlayer distance. These predictions promise that monolayer GSiC could be a remarkable candidate for novel type of light-emitting diodes utilizing its unique optical properties distinct from graphene, silicene and few layers GSiC.

Motivation & Objective

• To explore the electronic and optical properties of two-dimensional few-layer graphitic silicon carbide (GSiC), particularly monolayer and bilayer structures.
• To compare these properties with those of graphene and silicene, identifying unique characteristics in GSiC.
• To investigate the tunability of the bandgap in monolayer GSiC through in-plane strain.
• To examine the sensitivity of bilayer GSiC electronic structure to interlayer distance variations.
• To evaluate the potential of monolayer GSiC as a novel material for light-emitting diodes (LEDs) based on its distinct optical response.

Proposed method

• Employed density functional theory (DFT) to calculate the electronic band structures and optical response functions of monolayer and few-layer GSiC.
• Performed structural optimization to determine equilibrium lattice parameters and interlayer distances.
• Applied in-plane strain to the monolayer GSiC system to assess its effect on the bandgap energy.
• Varied the interlayer spacing in bilayer GSiC to analyze its impact on electronic bandgap and character.
• Calculated optical dielectric function and absorption spectra to evaluate light-emitting potential.
• Compared results with those of graphene and silicene to highlight differences in electronic and optical behavior.

Experimental results

Research questions

• RQ1 Does monolayer graphitic silicon carbide exhibit a direct or indirect bandgap, and how does it compare to graphene and silicene?
• RQ2 To what extent can the bandgap of monolayer GSiC be tuned by applying in-plane strain?
• RQ3 How sensitive are the electronic properties of bilayer GSiC to changes in interlayer distance?
• RQ4 What are the optical absorption characteristics of monolayer and few-layer GSiC, and how do they differ from those of graphene?
• RQ5 Can monolayer GSiC serve as a viable candidate for novel light-emitting devices based on its unique optoelectronic response?

Key findings

• Monolayer GSiC possesses a direct bandgap, distinguishing it from the zero-gap semimetallic behavior of graphene and the indirect gap of silicene.
• The bandgap of monolayer GSiC can be effectively tuned by applying in-plane tensile strain, indicating potential for strain-engineered optoelectronic devices.
• Few-layer GSiC (bilayer and beyond) exhibits an indirect bandgap, differing from the direct gap in monolayer form.
• The electronic structure of bilayer GSiC is highly sensitive to interlayer distance, with significant changes in bandgap and band dispersion observed upon variation.
• Optical absorption spectra of monolayer GSiC show strong, tunable absorption in the visible to near-infrared range, supporting its potential for light-emitting applications.
• The unique combination of direct bandgap and strong optical response positions monolayer GSiC as a promising alternative to graphene for optoelectronic and photonic devices.