Effects of Cu contents on defects formation in molecular dynamics simulations of ZnO:Cu films deposition

The development of p-type ZnO film is related to the acceptor doping and defects, which are difficult to assess. Copper doped ZnO (ZnO:Cu) film with varying Cu content on a ZnO(0 0 1) substrate were simulated using molecular dynamics simulations. The COMB3 potential was used to describe the interaction between the depositing and substrate atoms. The growth of the ZnO:Cu films on the ZnO(0 0 1) substrate was a 3D island mode. Numerous oxygen vacancies (VO), zinc vacancies (VZn) and dislocations existed in the deposition layers. Cu-Zn alloy clusters combined easily with Cu and Zn atoms, increasing the mass of the deposit. This resulted in the content of acceptor defect VZn in ZnO layers increasing with the increase of Cu atoms. This could explain the p-type characteristics of ZnO:Cu film.