A scanning electron microscope was used to inspect the results. Fig. 3a illustrates a monolayer of self-assembled PS nanospheres over photoresist. Areas of several hundred micrometres in length with uniform nanosphere arrays were obtained by using micropipette deposition. However, uniform sphere arrays of several inches are possible by other methods. The concentration of prepared PS nanospheres dilution is critical in controlling the number of layers because a low concentration would result in empty spaces among nanospheres and high concentration would cause multilayer. An SEM image of the sample after development process is shown in Fig. 3b which demonstrates highly ordered nano-holes arrays with approximate diameter of 250 nm (inset in Fig. 3b).