Nanocluster formation in Fe implanted GaN

The formation of Fe-clusters in wurtzite GaN implanted with 200 keV 57Fe ions at 350 ±C was investigated. Cluster sizes from few nanometers up to several 100 nm depending on ion fluence, implantation and annealing temperature have been observed for ion fluences between 4·1016 cm−2 and 1.6·1017 cm−2. A clear epitaxial relation between Fe and GaN was determined. X-ray diffraction, conversion electron Mössbauer spectroscopy, transmission electron microscopy and Auger electron spectroscopy were used for the characterization of the implanted samples. Mössbauer spectroscopy shows that precipitation of Fe occurs already during implantation.