The effect of Cu doping on the piezoelectric properties of ZnO systems: First-principles calculations

作者：Liu, Lin; Yu, Wentao; Zhao, Yujie; Zhu, Wensheng; Li, Jing; Wu, Lingkang^*; Wang, Hao

来源：International Journal of Modern Physics B, 2023, 2450324.

DOI：10.1142/S0217979224503247

• First-principles calculations
• ZnO
• Cu doping
• piezoelectric properties

First-principles calculations are performed, revealing a significant enhancement of the piezoelectric properties of wurtzite Zn36O36 upon the incorporation of a single Cu atom. Research has demonstrated that the piezoelectric constant d(33) reaches its maximum value at a doping concentration of 1.4% for Cu atoms. The lattice parameters a and c of Zn36O36 are decreased and the piezoelectric strain coefficient d(33) is increased by replacing one Cu atom in Zn36O36. It is found that elastic softening is the primary factor responsible for the increase of d(33) in Zn35Cu1O36. By differential charge density analysis, it is found that the covalency between Cu-O bonds is lower than that of Zn-O bonds, and the covalent bonding characteristics are weakened. Bader charge analysis shows that the charge of Cu is higher than that of Zn, indicating a more significant ionic bonding feature than that of Zn. Thus, a weaker covalent and stronger ionic bond are considered to play an essential role in promoting elastic softening for ZnO, which eventually promotes a significant enhancement in piezoelectric properties.

• 单位
  常州大学