Characterization of high dose Mn, Fe, and Ni implantation into p-GaN

The magnetization of p-GaN or p-AlGaN/GaN superlattices was measured after implantation with high doses (3-5 x 10(16) cm(-2)) of Mn, Fe, or Ni and subsequent annealing at 700-1000 degreesC. The samples showed ferromagnetic contributions below temperatures ranging from 190-250 K for Mn to 45-185 K for Ni and 80-250 K for Fe. The use of superlattices to enhance the hole concentration did not produce any change in ferromagnetic ordering temperature. No secondary phase formation was observed by x-ray diffraction, transmission electron microscopy, or selected area diffraction pattem analysis for the doses we employed. (C) 2002 American Vacuum Society.