A DFT STUDY OF QUATERNARY CHALCOGENIDE SEMICONDUCTORS Cu2ZnSnS(Se)(4) BY TRAN-BLAHA MODIFIED BECKE-JOHNSON AND HUBBARD POTENTIALS

The I2-II-IV-VI4 series of quaternary chalcogenides semiconductors have drawn wide interest for their potential application as solar-cell absorbers; In this paper, we present a study of electronic and optical properties of the equilibrium kesterite structure (KS) of Cu2ZnSnS(Se)(4) (CZTS(Se)), stannite structure (SS) of Cu2ZnSnS4 and secondary phases of KS-Cu2ZnSnS4 in the DFT frame. For this purpose, we used the Wien2k code based on the density functional theory (DFT) with the modified Becke-Johnson exchange potential mBJ and the Hubbard potential U, individually or combined (TB-mBJ, and TB-mBJ+U). The results are compared with those obtained using generalized gradient approximation GGA and local density approximation LDA approximations and the available experimental ones. The obtained results using TB-mBJ and TB-mBJ+U are in good agreement with the experimental results which are different from results obtained using GGA approximation and similar published ones using LDA approximation. Some electronic states appear above the Fermi level when we use GGA approximation. These states increase when we use TB-mBJ. This phenomenon can be recovered by using the U correction potential in combination with TB-mBJ correction potential