Fig. 2
From: Direction-specific interaction forces underlying zinc oxide crystal growth by oriented attachment
Face-specific interaction force measurements. a Representative force curves for ZnO(0001)-ZnO(000\(\bar 1\)) interaction in saturated aqueous solution. Point 1–2 presents the approach process until the jump-to-contact happened (point 2–3); then further push the tip to contact the substrate from point 3–4; after a short time to stabilize the interaction, tip retraction was performed (point 4–5) until a jump-from-contact happened (point 5–6). b Direction-specific interaction forces at different azimuthal orientation for ZnO(0001)-ZnO(000\(\bar 1\)) and ZnO(0001)-SiO2/Si and different loading rates for ZnO(0001)–ZnO(000\(\bar 1\)). c Data fitting for the different loading rates at each azimuthal orientation from 0° to 60° to obtain the equilibrium rupture force. Error bars in b and c represent the s.e. (n = 25). d Rupture forces at different azimuthal orientation after fitting using the multiple bond model developed by Friddle et al.29; Error bars derived from the fitting of the multiple bond model. Inset illustrates corresponding structure relationships between the tip and substrate crystals at selected azimuthal orientations (0°, 30°, 60°, and 90°)
