Table 1 Parameters for the four deposition configurations Configuration Rotational velocity (ps−1) Template geometry (d, s, h) NT-RGLAD 100 0, 0, 0 HT-RGLAD 100 6a, 10a, 14a HT-SGLAD 0 6a, 10a, 14a LT-RGLAD 100 6a, 10a, 8a The a (0.3615 nm) is the lattice constant for Cu. Results and discussion Figure 2a presents the front and top views of the morphology of the Cu-Al system obtained after the template-free rotational GLAD, indicating that there is no columnar structure formed. The upper row of Figure 2a
shows that the Al thin film grows in a layer-by-layer fashion on the Cu substrate, which is inconsistent with previous work [14, 15]. However, there are islands formed on the surface of the formed Al thin film when the deposition flux is small. The islands resulting from the shadowing effect serves as shadowing centers to facilitate the formation of columnar structures during further GLAD deposition. Recent work suggests FRAX597 cost that low incident energy may significantly enhance the click here possibility of columnar structure formation during the template-free NCT-501 price rotational GLAD [10]. In contrast, there are patterns of columnar structures formed during the template-assisted rotational GLAD or the static GLAD when templates are placed on the Cu substrate, as shown in Figure 2b,c,d.
Furthermore, most of the impinging Al atoms are received by the templates. Therefore, it clearly indicates that the presence of the templates can significantly facilitate the formation of columnar structures because of the intensified shadowing effect, given the limited
deposition flux. It should be noted that because of the presence of PBC next in the transverse directions of the substrate, the distance between the edge templates is larger than that between the templates within the simulation box, which may lower the possibility of columnar structure formation. Figure 2 Morphologies of the as-deposited nanostructures. (a) Template-free rotational GLAD; (b) high template-assisted rotational GLAD; (c) high template-assisted static GLAD; (d) low template-assisted rotational GLAD. The upper row shows the front views, in which atoms are colored according to their virtual types: red, blue, and yellow stand for boundary, thermostat, and mobile atoms, respectively; the bottom row shows the top views, in which atoms are colored according to their heights. Figure 2 also shows that the morphology of the columnar structures strongly depends on the parameters of the deposition configurations. Figure 2b shows that the height distribution of the columnar structures obtained through the high template-assisted rotational GLAD is not uniform, although the heights of the templates are the same. Furthermore, slight inclination of the axial of the columnar structures is observed. For the template-assisted static GLAD, the inclination is more pronounced than the template-assisted rotational GLAD, as shown in Figure 2b.