Effect of carrier doping and external electric field on the optical properties of graphene quantum dots

International Conference on Advances in Materials and Manufacturing Applications 2017

Basak, Tista^1 ; Basak, Tushima^2

Mukesh Patel School of Technology Management and Engineering, NMIMS University, Mumbai, India^1

Department of Physics, Mithibai College, Mumbai, India^2

关键词: Blue shift;    Carrier doping;    Charge doping;    External electric field;    Long-range Coulomb interaction;    Model Hamiltonians;    Optical spectra;    Transverse electric field;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/310/1/012014/pdf
DOI  :  10.1088/1757-899X/310/1/012014

来源: IOP

【 摘 要 】

In this paper, we demonstrate that the optical properties of finite-sized graphene quantum dots can be effectively controlled by doping it with different types of charge carriers (electron/hole). In addition, the role played by a suitably directed external electric field on the optical absorption of charge-doped graphene quantum dots have also been elucidated. The computations have been performed on diamond-shaped graphene quantum dot (DQD) within the framework of the Pariser-Parr-Pople (PPP) model Hamiltonian, which takes into account long-range Coulomb interactions. Our results reveal that the energy band-gap increases when the DQD is doped with holes while it decreases on doping it with electrons. Further, the optical absorption spectra of DQD exhibits red/blue-shift on doping with electrons/holes. Our computations also indicate that the application of external transverse electric field results in a substantial blue-shift of the optical spectrum for charge-doped DQD. However, it is observed that the influence of charge-doping is more prominent in tuning the optical properties of finite-sized graphene quantum dots as compared to externally applied electric field. Thus, tailoring the optical properties of finite-sized graphene quantum dots by manipulative doping with charge carriers and suitably aligned external electric field can greatly enhance its potential application in designing nano-photonic devices.