Ferromagnetic properties of GaN nanorods: Effect of silicon doping and hydrogenation

In this paper, we have investigated effect of Si doping and hydrogenation on room temperature ferromagnetism in GaN nanorods (NRs) grown on patterned Si (111) substrate by plasma assisted molecular beam epitaxy. Vibrating sample magnetometer measurements revealed that ferromagnetic properties enhanced with increased in Si concentration and maximum saturation of magnetization was about 0.023emu/g, which is three times higher than that of undoped GaN NRs. Hydrogenation of Si doped GaN NRs strongly suppresses the ferromagnetic behavior, while thermal annealing of hydrogenated GaN NRs revealed that recovery of ferromagnetic properties. Hydrogen compensates the free electron concentration in Si doped GaN NRs which tends to decrease ferromagnetic properties and recovery of ferromagnetic properties due to thermal dissociation of hydrogen atoms from GaN NRs. These results suggest that ferromagnetic properties enhanced in Si doped GaN NRs, which is possibly related to increase in free electron concentration.