Predicted lattice relaxation around point defects in zinc selenide - art. no. 035206

There is great interest in altering the electronic and consequent optical p roperties of wide-band-gap semiconductors through the use of selected addit ives (dopants). These effects depend on the way in which the impurity enter s the lattice structure, and the resulting possible lattice relaxation effe cts and their repercussions. There have been several calculations for the p oint defects in ZnSe based on pseudopotential approaches, with some differe nces in results among these; and, in the case of nitrogen substitution for the selenium, there Is a difference with experiment as to the expected size of relaxation effects around the defect. Thus it is useful to have calcula tions by a quite different technique. For that reason, as benchmark calcula tions, we have studied lattice relaxation around Zn and Se vacancies, and a round N-for-Se substitution sites in ZnSe [V-Se, (V-Se)(++), V-Zn, (V-Zn)(- -), N-Se, and (N-Se)(-)], using a full-potential, linear combination of muf fin-tin orbitals total energy calculation including an atomic force routine . We have obtained results for the lattice response of ZnSe in various conf igurations, and discuss these in comparison to the pseudopotential results and experiment. For the case of nitrogen substitution for selenium, we also present an independent experimental verification of previously reported re sults for the unusually large lattice relaxation surrounding this defect.