Direct evidence for implanted Fe on substitutional Ga sites in GaN

The lattice location of iron in thin-film, single-crystalline hexagonal GaN was studied by means of the emission channeling technique. Following 60-keV room-temperature implantation of the precursor isotope $^{59}$Mn at a dose of 1.0 $\times 10^{13}$ cm$^{-2}$ and annealing up to 900°C, the angular distribution of $\beta^{-}$-particles emitted by the radioactive isotope $^{59}$Fe was measured by a position-sensitive electron detector. The $\beta^{-}$-emission patterns around the [0001], [1102], [1101] and [2113] directions give direct evidence that the majority of Fe (80%) occupies substitutional Ga sites.