The origin of the P-type conductivity for Cu and Ag-doped NiO: Density functional theory study

NiO, as a promising transparent p-type semiconductor, was intensively studied in experiment. Due to the dif-ference of fabrication methods and defects concentration, it is difficult to make meaningful comparisons. In this work, the performance for Cu and Ag-doped NiO is fully evaluated by using the density functional theory method. Electronic structures show Cu and Ag substituting Ni (labeled as CuNi and AgNi) are deep acceptors, and the ionization energy e(0/-) for CuNi and AgNi are much higher than 0.20 eV. Our studies show the p-type conductivity for Cu and Ag-doped NiO mainly stems from the coexistent Ni vacancies (labeled VNi). The ioni-zation energy e(0/-) for CuNi (AgNi) plus VNi are 0.086 (0.012) eV. Under O-rich condition, the compounds M2O2 and M2O (M = Cu and Ag) are promising dopants sources. We expect this work could promote the fundamental understanding of the p-type conductivity for nonstoichiometric NiO as well as the Cu and Ag-doped NiO.

Automated summary

In this study, the performance of Cu and Ag-doped NiO was evaluated using the density functional theory method. It was found that CuNi and AgNi serve as deep acceptors with high ionization energy. The p-type conductivity of Cu and Ag-doped NiO mainly originates from coexistent Ni vacancies.