Large area laser interference patterning for periodic growth of individual ZnO nanowires

The growth of semiconductor ZnO nanowires in a periodic fashion is of great interest for many applications such as solar cells, field emission devices, light emitting diodes, and piezo-nanogenerators. Novel laser interference lithography techniques for the site-selective growth of ZnO nanowires on Gallium Nitride (GaN) substrate are described. A nanosecond pulsed Nd:YAG laser with 266nm wavelength is used in the experiments. Both laser interference ablation of GaN substrates and laser interference lithography of photoresist masks on GaN substrates are conducted to control the position and periodicity of grown individual ZnO nanowires. Simulations of both processes are presented. The nanowires, grown using a low temperature hydrothermal decomposition method on both types of substrates, follow the designed pattern, with a high degree of control in size, dimensionality, and uniformity. Well patterned and aligned individual ZnO nanowires on areas spanning one square-centimeter scale and onesquare-decimeter scale can be achieved by laser interference ablation and lithography respectively.