Morphology and surface reconstruction on RuO2 single crystals

The morphologies and surface dynamic processes on RuO2 single-crystal subst rates were studied using scanning tunneling microscopy (STM) under non-vacu um conditions. The as-grown oxide surfaces show a variety of constructs and aggregations of a-top atoms that form secondary microstructures with no di stinct periodicity. Atomically resolved images captured on adjacent terrace s of the same sample indicate differences in a-top atomic arrangements on a single-crystal surface. After annealing an as-grown sample in air at simil ar to 450 degreesC for 2 h. the STM images show an ordered, long-range surf ace reconstruction along the c-axis of the crystal lattice. Combined. this morphological diversity and structural rearrangement suggest motion and clu stering of the surface atoms at elevated temperatures. (C) 2001 Elsevier Sc ience B.V. All rights reserved.