Theoretical and experimental investigation of possible ferromagnetic ordering in wide band gap ZnO and related systems

Room temperature ferromagnetic ordering has been induced in the ZnO thin film by 26 keV C ion implantation. Several orders of resistivity reduction have been observed after C implantation. Ab initio calculations in the frame work of density functional theory indicates that C substitution at the oxygen vacancy site can induce magnetic moment in ZnO. C substitution at zinc vacancy site cannot produce any ferromagnetic moment although zinc vacancy in undoped ZnO induces the same. It has also been shown that ferromagnetic ZnO with sufficient hole concentration at room temperature cannot be realized by adjusting native vacancies only. After C substitution in the system, donor like states appear near the conduction band causing more n-type character compared to undoped ZnO.