Mossbauer Study Of Fe-57 In Gaas And Gap Following Mn-57(+) Implantation

Ion implantation provides a precise method of incorporating dopant atoms in semiconductors, provided lattice damage due to the implantation process can be annealed and the dopant atoms located on regular lattice sites. We have undertaken Fe-57 emission Mossbauer spectroscopy measurements on GaAs and GaP single crystals following implantation of radioactive Mn-57(+) ions, to study the lattice sites of the implanted ions, the annealing of implantation induced damage and impurity-vacancy complexes formed. The Mossbauer spectra were analyzed with four spectral components: an asymmetric doublet (D1) attributed to Fe atoms in distorted environments due to implantation damage, two single lines, S1 assigned to Fe on substitutional Ga sites, and S2 to Fe on interstitial sites, and a low intensity symmetric doublet (D2) assigned to impurity-vacancy complexes. The variations in the extracted hyperfine parameters of D1 for both materials at high temperatures (T > 400 K) suggests changes in the immediate environment of the Fe impurity atoms and different bonding mechanism to the Mossbauer probe atom. The results show that the annealing of the radiation induced damage is more prominent in GaAs compared to GaP.