First-Principles Study on Influences of Crystal Structure and Orientation on Band Offsets at the CdSCu2ZnSnS4 Interface

Abstract EN

Cu2ZnSnS4 (CZTS) has attracted much attention recently as an absorber layer material in a heterojunction solar cell.

Using the first-principles method, we calculate the band offsets for the CdS/CZTS heterojunction.

The valence band offset ΔEv is 1.2 eV for the (001) CdS/CZTS heterointerface and 1.0 eV for the (010) heterointerface, when CZTS is considered to crystallize in the kesterite structure.

When CZTS is considered to crystallize in the stannite structure, ΔEv=1.1 eV for the (001) heterointerface and ΔEv=1.3 eV for the (010) heterointerface.

In any case, the conduction band minimum of CZTS is higher than that of CdS, and the conduction band offset ΔEc is in a range between 0.1 and 0.4 eV.