X-ray study of step morphology of MgO(100) surfaces

Crystal truncation rod (CTR) X-ray scans were performed to investigate the step structures of MgO(100) surfaces prepared by mechanical polishing and subsequent thermal annealing in air. The mechanically polished surface contained steps with step heights of 1.67, 2, 3, and 5 atomic spacings, while the annealed surface contained steps with step heights of only 2 and 3 atomic spacings whose populations were less than those of the polished surface. The terraces between steps have been found expanded significantly after thermal annealing. The average terrace sizes estimated after thermal annealing were 110 × 7 Ų and 334 × respectively.