Effect of nitrogen as co-dopant in carbon and boron-doped ZnO clusters

•C, N atoms are more stable at O site than at the Zn site in (ZnO)n clusters, however B atom is more stable at Zn site.•C atom induces magnetic moment of 2 μB per C atom and N induces 1 μB per N atom.•C:N co-doped (ZnO)n clusters are more stable and magnetically enhanced as compared to N:N co-doped (ZnO)n clusters.•B:N co-doped clusters have high stability than C:N co-doped clusters.

The effect of N as co-dopant have been investigated on magnetic properties of C and B-doped (ZnO)n(ZnO)n clusters (n=1−16)(n=1−16) using spin-polarized density functional theory. Total energy calculations show that C and N more stable when substituted at O site, whereas B is more stable at the Zn site. The B:N co-doping is energetically more stable than C:N which is more stable than N:N doping. C and N atoms do not show tendency to form clusters when doped separately. The magnetic moment (MM) of C-doped ZnO clusters is enhanced significantly with N co-doping. The MM of 2 μB, 1 μB and 1 μB per atom is induced due to C, N and B respectively. The MM of 3 μB or 5 μB and 2 μB or 4 μB are observed for co-doping of 2C:N and C:2N respectively. In contrary, the MM in 2B:N and B:2N co-doped (ZnO)n(ZnO)n remains 1 μB for n=2−4, 12 and 16. The results are in agreement with the available theoretical results.