Study of oxidized Cu(1Â 1Â 0) surface using noncontact atomic force microscopy

Formation of an oxidized overlayer onto Cu(1 1 0) surface was examined by means of noncontact atomic force microscopy at oxidation temperature ranging from RT to 610 °C and an O2 exposure from 104 to 105 L. Atomic resolution images of an c(6 × 2) reconstruction exhibited different contrasts from those obtained in STM studies and coincided well with the presented structural model. The surface oxidized at RT in the present exposure range exhibited a rough morphology, and was observed to undergo a partial transition to the c(6 × 2) structure at 25,000 L. At an oxidation temperature of 360 °C an well-ordered c(6 × 2) reconstruction was observed to cover the entire terrace irrespective of the exposure amount. Characteristic point defect was also imaged on this surface in detail. At an oxidation temperature of 610 °C a (2 × 1) reconstruction was observed to coexist on the same terrace with c(6 × 2). Formation mechanism of this coexistence phase in this high temperature regime is discussed.