Figure 1.

Side view and top view of the ZnO(101̅0) model are illustrated in (a) and (b), respectively. The GA explored the configurations of ZnO_x (x = 6–12) with the top two atomic layers shown in the dashed rectangle. The third layer can be relaxed while the fourth layer is frozen during the optimization process. Znn_OV (n = 1–3) represents the new sites due to the departure of oxygen, while Zn_3c and O_3c denote intrinsic three-coordination sites on the surface.