ROLE OF CODOPANTS IN THE LUMINESCENT OUTPUT FROM SI-ER

A crystal-field model for the electronic structure of the Er3+ ion in silicon is presented. The parameters within the model are adjusted in order that the Stark energy splittings within the f shell reproduce th e observed spectral features in a Si:Er sample that is codoped with ni trogen. The dominant crystal field possesses tetrahedral symmetry. Sev eral additional spectral features are attributed to local mode vibrati onal sidebands. From this analysis, I conclude that the role of the co dopants is to isolate the Er ion so that the relaxation energy does no t go into the production of lattice phonons. (C) 1996 American Institu te of Physics.