Room-temperature ferromagnetism in p-type (Mn, N)-codoped ZnO thin films achieved by thermal oxidation of sputtered Zn3N2:Mn films

P-type (Mn, N)-codoped ZnO films have been fabricated by oxidative annealing of sputtered Zn2N3 : Mn films on silicon substrates at 550 deg C in flowing O2 ambient. X-ray diffraction and x-ray photoelectron spectroscopy studies reveal that the Mn and N ions incorporated into the ZnO lattice are divalent Mn2+ and trivalent N3- ions, respectively. Ferromagnetism with Curie temperature above 300 K was observed in p-type (Mn, N)-codoped ZnO films. The results indicate that holes are favourable for ferromagnetic ordering in doped Mn2+ ions in ZnO, in agreement with recent theoretical studies.