Spectroscopic Characterisation of Erbium Impurity in Crystalline Silicon

摘要

A fully numerical scheme for the computation of energy levels and wave functions of rare-earth impurities in crystalline solid matrices has been developed. In this paper, application to the specific case of the erbium ion in semiconductors is taken as example. The lifting of spin-orbit degeneracy due to ligand fields of neighbouring host-crystal atoms in cubic, trigonal, tetragonal and orthorhombic co-ordination is quantitatively considered. Existing data for the well-identified luminescence spectra Si-Er-C, the main cubic spectrum, and of the low-symmetry centres Si-Er-1 and Si-Er-O1,2 are interpreted within the level diagram. Adding the Zeeman Hamiltonian, the g tensors for further splitting in a magnetic field, removing all degeneracy, were calculated. Principal g values for a recently reported centre Si-OEr-1 of monoclinic symmetry can be well explained by the calculations.