Full text loading...
Assumed cross-sectional geometry of a semi-cylindrical nanowire in a groove with angle forming a contact angle with the substrate. The radius of the wire varies with position z along the length of the groove. This example is for . Other examples are shown in Fig. 2 .
Examples of different groove/wire configurations (a) flat substrate ( ), (b) full contact convex wire ( ), (c) flat wire ( ), and (d) concave wire ( ). The other case of partial contact ( ) resulting in two free surfaces is shown in Fig. 1 .
The β function characterizes the geometric effects of changing the contact angle θ and the groove angle ψ on the instability. A system is unstable if and stable if . Two such stable configurations are shown in Figs. 2(c) and 2(d) .
Predictions of (a) wavelength from (16), and (b) growth rate from (18) for a number of different groove angles ( and 45°) and evaporation rates (σ = 0, 0.2, and 0.5). The model shows good correspondence with the exact solution of McCallum et al. 14 for a flat substrate ( and ) shown in (a) as a dotted line.
The experimental measurements of Huang et al. 1 for the wavelength of a nanowire on a flat substrate (symbols) are well approximated by a linear temperature dependence (dashed-dotted line). This increase in the wavelength is consistent with a change in the dissipative mechanism (σ) or a change in the contact angle (θ) as shown.
Article metrics loading...