Effects of high-dose Mn implantation into ZnO grown on sapphire

ZnO films, grown by pulsed-laser deposition on c-plane Al2O3 substrates were annealed at temperatures up to-600degreesC to produce n-type carrier concentrations in the range 7.5x10(15)-1.5x10(20) cm(-3). After high-dose (3x10(16) cm(-2)) Mn implantation and subsequent annealing at 600degreesC, all the films show n-type carrier concentrations in the range 2-5x10(20) cm(-3) and room temperature hysteresis in magnetization loops. The saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial anneal temperature, suggesting that carrier concentration alone cannot account for the magnetic, properties of ZnO:Mn, and that factors such as crystalline quality and residual defects play a role. (C)2004 American Institute of Physics.