Lattice site and diffusion of ion-implanted Li in as-grown and Se-rich ZnSe
Bharuth-Ram, K Restle, M Hofsass, H Ronning, C Wahl, Ulrich #
Elsevier science bv
Physica b-condensed matter vol:274 pages:875-878
The implantation sites and diffusion of Li in as-grown and Se-rich ZnSe has been studied with emission channeling measurements on the alpha-particles emitted in the decay of radioactive Li-8 probes implanted in single-crystal samples. At implantation temperatures below 180 K the Li atoms are immobile at tetrahedral interstitial sites, but a site change sets in at 200 K, and above 250 K the Li atoms occupy mainly substitutional sites. In Se-rich ZnSe the interstitial Li fraction (f(T)) shows partial recovery between 260 and 360 K, a phenomenon which may be attributed to Li trapping at interstitial Se. Implantation dose, however, has a strong influence on the observed channeling and blocking patterns. Maximum f(T) is achieved at T greater than or equal to 400 K where the fraction at interstitial sites is an order of magnitude lower. At higher temperatures ( approximate to 550 K) the Li atoms dissociate from their substitutional sites and diffuse to the surface in the Se-rich sample and to extended defects in the implantation region in the as-grown sample. (C) 1999 Elsevier Science B.V. All rights reserved.