Morphology and interface structure of α-Fe2O3 islands grown on sapphire by ion-implantation and annealing

The morphology and interface structure of alpha-Fe2O3 islands grown on alpha-Al2O3 single crystals (sapphire) by Fe-ion-implantation and annealing in an oxidizing atmosphere have been studied using transmission electron microscopy. The alpha-Fe2O3 islands have the orientation relationship of [0 0 0 1](alpha-Fe2O3)parallel to[0 0 0 1](sap)p(hire) and (1 1 (2) over bar 0)alpha-Fe2O3 parallel to(1 1 (2) over bar 0)(sapphire) with sapphire. The typical outline of alpha-Fe2O3 islands consists of two (0 0 0 1) and six {1 0 (1) over bar 2} planes. The interfaces between alpha-Fe2O3 islands and sapphire are semicoherent, that is coherent regions separated by misfit dislocations at the interfaces. When imaged along the [(1) over bar 1 0 0](sapphire) direction, the projected Burgers vector is determined to be 1/6[1 1 (2) over bar 0](sapphire). When imaged along the [(1) over bar 1 0 0](sapphire) direction, the projected Burgers vector is determined to be 1/2[(1) over bar 1 0 0](sapphire). These misfit dislocations form a network structure at the interface to accommodate the mismatch between the lattices of the alpha-Fe2O3 and the alpha-Al2O3. (C) 2008 Elsevier B.V. All rights reserved.