Computational investigation of the electronic and optical properties of planar Ga-doped Graphene

TL;DR

This study uses density functional theory to simulate how gallium doping affects the electronic and optical properties of graphene, revealing changes in conductivity, band structure, and electron mobility with varying impurity levels.

Contribution

It provides a detailed computational analysis of gallium-doped graphene's electronic and optical responses, highlighting the effects of impurity doping on its properties.

Findings

Doping disrupts electronic structure at low levels due to impurity scattering.

Graphene maintains metallic behavior even at higher doping levels.

Gallium introduces new electronic bands that alter the Dirac cone and improve electron mobility.

Abstract

We simulate the optical and electrical responses in gallium-doped graphene. Using density functional theory with a local density approximation, we simlutate the electronic band structure and show the effects of impurity doping (0-3.91\%) in graphene on the electron density, refractive index, optical conductivity, and extinction coefficient for each doping percentages. Here, gallium atoms are placed randomly (using a 5-point average) throughout a 128-atom sheet of graphene. These calculations demonstrate the effects of hole doping due to direct atomic substitution, where it is found that a disruption in the electronic structure and electron density for small doping levels is due to impurity scattering of the electrons. However, the system continues to produce metallic or semi-metallic behavior with increasing doping levels. These calculations are compared to a purely theoretical 100\% Ga sheet for comparison of conductivity. Furthermore, we examine the change in the electronic band structure, where the introduction of gallium electronic bands produces a shift in the electron bands and dissolves the characteristic Dirac cone within graphene, which leads to better electron mobility.