Induced Growth from a Ag Gas on Cu(111)

Abstract

We investigate the induced growth of a Ag layer on a Cu(111) surface by variable low-temperature scanning tunneling microscopy between 100 and 140 K at submonolayer coverage. Without any interference by the scanning process, the Ag atoms form a two-dimensional gas on the Cu(111) surface. Imaging the surface at elevated voltage induces nucleation and growth of one-dimensional Ag stripes of monolayer height, eventually filling the surface of the imaged area completely. The stripes consist of rods of atoms with a preferential length of (1.88 ± 0.10) nm, corresponding to approx. seven or eight Ag atoms on eight to nine Cu hollow sites. At a ratio of approximately 1:3, rods of double length are the second most observed species. The rods stack in the ⟨112⟩ directions at the √3 distance of Cu(111). Although all equivalent three surface directions are observed, their abundance is not equally distributed, such that the rod direction aligned with the fast scanning direction predominates. At slow growth rates, it is possible to create a striped pattern with one surface direction only.

In Situ Growth and Bias-Dependent Modification of NaBr Ionic Layers on Ag(111)

“…The in situ growth is realized by measuring the filling of the terraces by plotting the uncovered area after the filling-in time. 36 Here, for a terrace of around 6 × 10 2 nm 2 , the filling takes roughly 120 scanning of the surface within 7000 s. A curve analysis reveals a power law decay, which is fitted (Figure 4d) by the potential decay law a−b*x c with the exponent of ≈2/3 as expected for diffusion-limited ripening. 44 The in situ growth layer is characterized by measuring the apparent height and atomic resolution images.…”

“…35 Moreover, scanning at elevated voltage induced one-dimensional stacked rods with specific lengths from mobile Ag atoms on Cu(111). 36 In this article, we report on the bias-dependent layer modification and the growth of a NaBr layer on Ag(111) at room temperature. The deposition at 270 to 298 K leads to twoor three-atomic layer high islands.…”

“…STM manipulation is a technique for modifying a surface or performing chemical reactions by precisely controlled tip–sample interactions. − The different manipulation capabilities using tunneling electrons , or electric fields between tip and sample − were extensively explored on metals, semiconductors, and insulating layers. − Concerning ionic layers, one report demonstrated cutting, moving, and cracking of a NaCl bilayer at cryogenic temperature by approaching the tip close to the surface . In another report, a NaCl layer was removed and reformed using the STM tip .…”

Temperature-Dependent Accommodation of Two Lattices of Largely Different Size during Growth

“…Third, a possible growth process: If the rods were stable entities that diffused over the surface to eventually stack to stripes, then the reason was a kinetic limitation. Observation of longer rods in an induced growth process does not favor this second possible reason [18]. In the same study, the rods appear usually at their full length.…”

“…The growth behaviour is markedly different at lower temperature between 120 and 170 K. At low coverage, there is no indication of the adsorbates in the STM images. Only by scanning at elevated voltage [18] or after deposition of a full monolayer, the adsorbates get visible. Then, the whole surface is completely covered at uniform height (Figure 2a).…”