Scanning tunneling microscopy (STM) studies were conducted on the surfaces of NbC0.75(100) and NbC0.865(110) single crystals after in-situ cleaning treatments of sputtering and annealing cycles. STM images show atom-resolved structures on both surfaces. On NbC0.75(100), localized areas of a square (1x1) structure were observed, together with regions of hexagonal structure, indicative of a coexisting surface phase, possibly that of Nb4C3-x. On the NbC0.865(110) surface, a ridge-and-valley grating structure consisting of both (4x1) and (5x1) geometries was observed over large areas. The nanometer-scale faceting phenomenon may be common to the (110) surfaces of most transition-metal carbides.
Corresponding author: M. Schmid (schmid).
Users with online access to Surf. Sci. can load the article from the publisher.