Fig. 3
From: Direction-specific interaction forces underlying zinc oxide crystal growth by oriented attachment
Maximum and minimum rupture forces and adhesion-free energies of ZnO(0001)–ZnO(000\(\bar 1\)). a Force versus tip contact area; b force normalized to tip contact area; c the corresponding adhesion-free energy versus contact area; d adhesion-free energy normalized to tip contact area. Tip diameters are noted
