A closer inspection reveals that most clusters are surrounded by

A closer inspection reveals that most clusters are surrounded by dark holes in the substrate which indicates that even at RT, metallic

adsorbate reacts with Ge. The formation of Ni-induced structural defects in semiconductor surfaces has been widely reported in the literature of the subject, e.g., [20]. click here Figure 1 Empty-state STM image showing the formation of clusters after Ni deposition onto Ge(111)-c(2 × 8) surface at RT. The initial Ni coverage is approximately 0.1 ML. The image size and bias voltage are 80 × 80 nm2 and 1.5 V, respectively. Inset: small-scale (30 × 25 nm2) image zoomed from the large area showing that clusters have a tendency to accumulate at boundaries between the different c(2 × 8) domains. Figure 2 shows the Ag/Ge(111)-√3 × √3 surface with 0.1 ML Ni deposited at RT. Here, clusters seem to be randomly distributed Selleckchem PI3K Inhibitor Library without concentrating at the terrace edges, which indicates that the surface diffusion 4EGI-1 chemical structure of the species at RT is suppressed. In the area between the clusters, a defect-free √3 × √3 structure is clearly resolved (see inset in Figure 2) which suggests that

there is no chemical reaction between the deposit and the surface. Therefore, we argue that the clusters are composed of pure Ni atoms rather than Ni-Ge compounds. Figure 2 Filled-state STM image taken after deposition of 0.1 ML Ni onto Ag/Ge(111)-√3 × √3 surface at RT. The image size is 80 × 80 nm2, and the bias voltage is -1.6 V. Inset: small-scale (24 × 22 nm2) image showing this website that clusters are randomly distributed on the surface. Annealing the surfaces with deposited materials within the range from 470 to 770 K results in the appearance of a variety of objects. While most of them appear only on either Ni/Ge(111)-c(2 × 8) surface (Figure 3) or Ni/Ag/Ge(111)-√3 × √3 surface (Figure 4), some structures commonly form on both of them (Figure 5). Figure 3 STM images showing Ni-induced structures on Ge(111)-c(2 × 8) surface. (a) Ring-like defects in single

and trimer configurations. Inset: 7 × 7 nm2 filled-state image taken at a sample bias of -0.6 V, showing ring-like defects. (b) 2√7 × 2√7 islands are enclosed by solid circles, whereas the 3 × 3 island is enclosed by a dotted circle. Insets: 12 × 10 nm2 images of the same 2√7 × 2√7 island taken at a positive (upper inset) and a negative (lower inset) bias voltage. (c) Empty-state image of a magnified 3 × 3 island. Inset: 13 × 15 nm2 filled-state image of the same island. Image size is indicated in each image. The notations in left upper corners represent the specified structures. Corresponding schematic diagrams against a background of the Ge(111)-c(2 × 8) structure are shown in right half parts. Figure 4 Empty-state STM images showing Ni-containing structures on Ag/Ge (111)-√3 × √3 surface. (a) Triple-hole defects which appear after annealing between 470 and 570 K. (b) Long islands (enclosed by circles) which appear after annealing above 670 K.

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