Unique nanopore pattern formation by focused ion beam guided anodization

The fabrication of ordered porous templates in large areas with sophisticated patterns beyond mono-sized pores in hexagonal packing remains a great technical challenge. Conventional anodization cannot overcome this limitation and a new approach needs to be sought. This study is focused on designing pore patterns in square and hexagonal arrangements via focused ion beam lithography with varying interpore distances in order to form organized pore arrays with more sophisticated patterns. The results demonstrate that the small pores from the anodization can be meshed with the larger pores from the focused ion beam lithography and unique, complicated nanopore patterns can be created. Large pore patterns that cross the grain boundaries are also made possible with the guidance of the pores from focused ion beam lithography. A fundamental pore pattern formation mechanism is proposed.