Tunable band gap and optical properties of surface functionalized Sc_2C monolayer

Using the density functional theory, we have investigated the electronic and optical properties of two-dimensional Sc₂C monolayer with OH, F, or O chemical groups. The electronic structures reveal that the functionalized Sc₂C monolayers are semiconductors with a band gap of 0.44-1.55 eV. The band gap dependent optical parameters, like dielectric function, absorption coefficients, reflectivity, loss function, and refraction index were also calculated for photon energy up to 20 eV. At the low-energy region, each optical parameter shifts to red, and the peak increases obviously with the increase of the energy gap. Consequently, Sc₂C monolayer with a tunable band gap by changing the type of surface chemical groups is a promising 2D material for optoelectronic devices.