Design and Simulation of G/Si Schottky Junction Solar Cell with Graphene Quantum Dots as Potential Barrier

Graphene (G)/Si Schottky junction solar cells (SJSCs) suffer from very low conversion efficiency due to the weak built-in electric field at the interface of graphene and Si. In this study a G/Si SJSC with an interlayer of graphene quantum dots (GQDs) is introduced. GQDs act as a potential barrier resulting in the enhancement of the built-in electric field. We compute the electrical properties of the graphene layer based on the Kubo-Drude formalism where its thickness and Fermi level are set to 0.34 nm and 0.3 eV , respectively. We calculate the electrical permittivity of GQDs through the Cole-cole model where, its diameter and height consider to 66 nm and 6 nm , respectively. Results of the simulation reveal a 27% increment in short circuit current density despite decreased absorption compared to cell without GQDs. Also, the conversion efficiency (ɳ) of the G/Si SJSC boosts up to 28% by embedding 11 layers of GQDs between graphene and Si layers. Finally, a ɳ equal to 10.4% is reported for G/Si SJSC for an absorber layer thickness of 2400 nm .