External Electric Field-Induced the Modulation of the Band Gap and Quantum Capacitance of F-Functionalized Two-Dimensional ScC.

The modulation of electronic properties and quantum capacitance of ScCF under a perpendicular external E-field was investigated using density functional calculations for the potential application of nanoelectronics and nanophotonics. ScCF has an indirect band gap of 0.959 eV without an E-field. Furthermore, it undergoes a semiconducting-metallic transition under a positive E-field and a semiconductor-insulator transition under a negative E-field. The application of the negative E-field makes ScCF have an indirect band gap. Sc-d, F-p, and C-p states are mainly responsible for the significant variation of the band gap. ScCF under an external E-field always keeps the character of a cathode material under the whole potential. Especially, ScCF under a negative external E-field is more suitable for the cathode material due to its much smaller ||/|| with much higher . The charge analysis is further performed.