First-principles study on the effect of biaxial strain on the carrier lifetime and absorption spectrum redshift of (S, Se, Te) double-doped ZnO

Considering the mismatch of lattice constants between the substrate and the (S, Se, Te) double-doped ZnO system and of the thermal expansion coefficients between the substrate and the doped system, the doped system was subject to external strain. Previous studies have neglected this issue. In the current research, we first applied biaxial strain on the model and then performed density functional theory calculation. The effects of applying different strains on the stability of the doped system, the red shift of the absorption spectrum, the trap effect, and the carrier lifetime were determined. The research results showed that Zn36SSeO34, Zn36STeO34, and Zn36SeTeO34 systems had smaller formation energies and better stability under the Zn-rich condition than under the Orich condition. All doped systems had negative cohesive energies and good stability. With the synergistic effect of strain and doping, when the biaxial compressive strain of the Zn36STeO34 system was - 5%, the hole-electron separation was good, the trap effect was substantial, the hole life increased, the absorption spectrum had a better red shift, and the oxidation reaction improved. These findings had a certain theoretical guiding effect on photocatalysts for the decomposition of water for oxygen production.