The characteristics of interface misfit dislocations for epitaxial α-Fe_2O_3 on α-Al_2O_3(0001)

摘要

α-Fe_2O_3(0001) films of thickness equal to ～7 nm and ～70 nm were epitaxially grown on α-Al_2O_3 (0001) by oxygen plasma- assisted molecular beam epitaxy. The interfaces were characterized using thigh resolution transmission electron microscopy, electron energy-loss spectroscopy, and X-ray diffraction. The interface exhibited coherent regions separated by equally-spaced misfit dislocations. When imaged form the [2110] direction, the dislocation spacing is 7.0±1.1 nm for the 70-nm-thick specimen, and 7.2±0.1 nm for the 7-nm-thick specimen.