Inversion domain boundaries in ZnO with additions of Fe2O3 studied by high-resolution ADF imaging

✍ Scribed by Frank Wolf; Bert H. Freitag; Werner Mader

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 781 KB
• Volume: 38
• Category: Article
• ISSN: 0968-4328
• DOI: 10.1016/j.micron.2006.07.021

✦ Synopsis

Columns of metal atoms in the polytypoid compound Fe 2 O 3 (ZnO) 15 could be resolved by high angle annular dark field imaging in a transmission electron microscopy (TEM)/STEM electron microscope -a result which could not be realized by high-resolution bright field imaging due to inherent strain from inversion domains and inversion domain boundaries (IDBs) in the crystals. The basal plane IDB was imaged in ½1 1 0 0 yielding the spacing of the two adjacent ZnO domains, while imaging in ½2 1 1 0 yields the position of single metal ions. The images allow the construction of the entire domain structure including the stacking sequence and positions of the oxygen ions. The IDB consists of a single layer of octahedrally co-ordinated Fe 3+ ions, and the inverted ZnO domains are related by point symmetry at the iron position. The FeO 6 octahedrons are compressed along the ZnO c-axis resulting in a Fe-O bond length of 0.208 nm which is in the range of Fe-O distances in iron containing oxides. The model of the basal plane boundary resembles that of the IDB in polytypoid ZnO-In 2 O 3 compounds.