The zero bandgap of graphene limits its utilization in optoelectronics. Quantum confinement in finite-size graphene structures, such as graphene quantum dots (GQDs) and holey GQDs, may offer a path for generating a wide range of HOMO-LUMO gaps. Edge terminations and pore passivations in these structures provide further means to alter their optical properties. In this work, we study the structural stabilities and optical properties of GQDs and holey GQDs with different sizes, edge terminations, and pore passivations, using density functional theory (DFT) as well as time dependent DFT. We find that the optical spectra of GQDs depend primarily on their size. Edge termination has a small influence on the spectra; shifting the absorption peaks by ~ 0.2 eV, which gets smaller for larger GQDs. Creation of pores in GQDs lead to the emergence of new peaks in their absorption spectra. Pore passivation seems to have the biggest effect on the absorption spectra of holey GQDs, while their termination leads to slight shifts in their peaks. Our results can be used to develop promising materials for many applications, such as biological sensors, and optoelectronic devices.
|Original language||English (US)|
|Journal||Physica E: Low-Dimensional Systems and Nanostructures|
|State||Published - Jan 6 2021|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-14
Acknowledgements: The authors would like to acknowledge the use of the computing resources through the computational Cy-Tera Project (NEA YΠOΔOMH/ΣTPATH/0308/31), which is co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research Promotion Foundation. We would like to acknowledge the support of the supercomputing facility at the Bibliotheca Alexandrina, Alexandria, Egypt. A. Maarouf would like to acknowledge the use of the resources of the Supercomputing Laboratory at KAUST, Thuwal, KSA.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics