E-Mail IMAGE: Scanning electron microscopy images of newly fabricated highly ordered nanohole arrays in tungsten, iron, cobalt and niobium oxide layers. view more Credit: Tokyo Metropolitan University Tokyo, Japan - Scientists from Tokyo Metropolitan University have developed a new method for making ordered arrays of nanoholes in metallic oxide thin films using a range of transition metals. The team used a template to pre-pattern metallic surfaces with an ordered array of dimples before applying electrochemistry to selectively grow an oxide layer with holes. The process makes a wider selection of ordered transition metal nanohole arrays available for new catalysis, filtration, and sensing applications.