Lattice site occupation of iodine implanted into aluminium

Abstract

The lattice site occupation of iodine ions implanted into aluminium single crystals at 5 and 293 K was determined by in situ MeV He + ion channeling. After implantation at 5 K the iodine atoms occupy substitutional and other regular interstitial positions. Upon annealing to 293 K most of the iodine atoms shift to near-octahedral sites. The relocation is attributed to the formation of iodine-hexavacancy configurations. This complex is also formed during implantation at 293 K. The near-octahedral fraction at 293 K was measured as a function of iodine concentrations. At concentrations of about 0.003% I in Al 〈110〉 the peak height in the center of the channel was about 2.4 + 0.3. Increasing the concentration, the peak height decreases to 1.3 at 0.1% I and to 1.0 at 1.5% I.