Abstract
Ion implantation is a superior post-synthesis doping technique to tailor the structural properties of materials. Via density functional theory (DFT) calculation and ab-initio molecular dynamics simulations (AIMD) based on stochastic boundary conditions, we systematically investigate the implantation of low energy elements Ga/Ge/As into graphene as well as the electronic, optoelectronic and transport properties. It is found that a single incident Ga, Ge or As atom can substitute a carbon atom of graphene lattice due to the head-on collision as their initial kinetic energies lie in the ranges of 25–26 eV/atom, 22–33 eV/atom and 19–42 eV/atom, respectively. Owing to the different chemical interactions between incident atom and graphene lattice, Ge and As atoms have a wide kinetic energy window for implantation, while Ga is not. Moreover, implantation of Ga/Ge/As into graphene opens up a concentration-dependent bandgap from ~0.1 to ~0.6 eV, enhancing the green and blue light adsorption through optical analysis. Furthermore, the carrier mobility of ion-implanted graphene is lower than pristine graphene; however, it is still almost one order of magnitude higher than silicon semiconductors. These results provide useful guidance for the fabrication of electronic and optoelectronic devices of single-atom-thick two-dimensional materials through the ion implantation technique.
Highlights
Ion implantation is a widely used technique to modify the structural and electronic properties of various materials in the semiconductor industry. For bulk materials, such as silicon-based semiconductor, the alien species can be introduced into the near-surface region of target material under irradiation of accelerated ion beams, and the concentration and depth distribution of doping atoms can be controlled by adjusting the flux and kinetic energy of incident ions
Two-dimensional materials usually have a narrow kinetic energy window since the kinetic energy of incident ions should be high enough to displace the target atoms yet low enough to be trapped in the lattice [5,6,7]
As proposed by Kantorovich and Rompotis [22], the collision process of an incident projectile and surface can be studied through ab-initio molecular dynamics simulations (AIMD) using stochastic boundary conditions (SBC) derived from the generalized Langevin equation (GLE), which performs as an NVT thermostat
Summary
Ion implantation is a widely used technique to modify the structural and electronic properties of various materials in the semiconductor industry. For bulk materials, such as silicon-based semiconductor, the alien species can be introduced into the near-surface region of target material under irradiation of accelerated ion beams, and the concentration and depth distribution of doping atoms can be controlled by adjusting the flux and kinetic energy of incident ions. Two-dimensional materials usually have a narrow kinetic energy window since the kinetic energy of incident ions should be high enough to displace the target atoms yet low enough to be trapped in the lattice [5,6,7]. It is indispensable to unveil the microscopic dynamic process of ion implantation, investigate the structural, electrical, optical and transport properties of ion-implanted graphene further for potentially practical application
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