Magnetic, structural and electronic properties of Fe implanted GaN

The request for room-temperature diluted magnetic semiconductors resulted in a large interest in GaN containing transition metals. In contrast to the (Ga,Mn)N-system, the origin of the ferromagnetism in Fe implanted GaN is still not sufficiently investigated. The formation of secondary phases and valence states of Fe play an important role in the discussion of the source of the ferromagnetism.
In this study, the electronic, structural and magnetic properties of p-GaN implanted with Fe+ (1 - 16 · 1016 cm^-2) at 350° C and subsequently annealed at 650° - 1000° C were examined by conversion electron Mössbauer spectroscopy, x-ray diffraction, transmission electron microscopy and magnetometry.
First experiments show ferromagnetic behaviour above room temperature in samples implanted with the highest amount of Fe. First x-ray diffraction and conversion electron M¨ossbauer spectroscopy measurements reveal the creation of alpha-Fe-clusters which are most likely responsible for the ferromagnetism.