Bonding and electronic properties of the Cu2ZnSnS4/WZ-ZnO interface from first-principles calculations

We theoretically explored the interface structure, binding energy, band offsets and electronic properties of the CZTS (1 0 2)/WZ-ZnO (1 1 0) interface from first-principles calculations. The interface has a small lattice mismatch of less than 3.2%. The interface binding energy is about -0.21 J m(-2). The values of band offset indicate that such an interface belongs to the type-I heterojunction. New electronic density of states, the so called interface states, appear near the Fermi level. These states are attributed to Cu 3d, Sn 5s, S 3s and 3p orbitals on the first CZTS layer, Zn 4s and 3d, O 2s and 2p orbitals on the first WZ-ZnO layer. The orbital hybridizations and charge transfers on both sides strengthen the interfacial adhesion.