ERBIUM POINT-DEFECTS IN SILICON

The possible technological importance of rare-earth-doped semiconducto rs has led to great interest in these materials. However, little at th e atomic level is hitherto known about such defects in the host lattic e. Using first-principles calculations, the nature of erbium point def ects in crystalline silicon is investigated. The total energy of an er bium point defect at several high-symmetry sites and with two differen t oxidation states is computed. Among the configurations studied, the minimum-energy one is Er3+ at a tetrahedral interstitial site. The nat ure of the Er-related defect levels is determined.