Two-dimensional scandium-based carbides (MXene): Band gap modulation and optical properties

Two-dimensional MXene materials with proper direct-band gap are especially desirable for photoelectric applications. Herein a new scandium-based carbide MXene (ScNbCO2) with direct band gap of ∼1.40 eV has been predicted by doping Nb transition metal and strain in terms of density-functional theory. The Nb-doping changes into direct band gap of 1.84 eV from indirect band gap of 2.96 eV of Sc2CO2. Attractively, the direct band gap of ScNbCO2 of ∼1.40 eV is further attained by stain effect. Especially, an increase of ∼20 times is achieved in the case of 3% uniaxial ScNbCO2. It reveals that these metal-doping MXene materials are promising to develop new light-electron conversion components.