Self-organization of ZnO wrinkles oriented by patterned PMMA templates

In this study, well-ordered ZnO wrinkles were fabricated by sol–gel derived ZnO films via heat treatment at 400 °C for 2 h with the assistance of polymethymethacrylate (PMMA) templates. PMMA templates with various patterns were employed to investigate the effects of template geometries on arrangements of the formed ZnO wrinkles. The influence of thickness on the transformation of the entire resulting structures of the spin-coated ZnO sol–gel films is discussed. With 2-dimensional arrangement of PMMA patterns, more than two orientations of wrinkled ZnO can be induced in one template. By controlling the arrangement of PMMA patterns and thickness of ZnO sol–gel films, specific circular, hexagonal, triangular and triangular-star complex structures were produced due to the constrained shrinkage force of the ZnO films applied toward the PMMA side walls during drying. By this technique, we can obtain 3-dimensional ZnO structures that conventional photolithography and nano-imprinting lithography are hard to achieve in few process steps.