Domain-boundary structures in Ce-doped alpha-(Si-Al-O-N)

The incorporation of large Ce ions into the interstitial sites in an alpha- ( Si-Al-O- N) crystal structure is found to have produced a high density of structural defects. The defects are of planar nature and connect to form d omain boundaries. Analysis via transmission electron microscopy has reveale d that only a single lattice translation of 1/3 [10 (1) over bar0] type is involved in the formation of domains which are enveloped by some specific f aces in this strongly bonded covalent compound, that is (0001), {10 (1) ove r bar1} and the common surface with the matrix crystal on {10 (1) over bar0 }. Development of the domain-boundary structures is discussed via the appli cation of image simulation based on different structural models of defects.