Images of Barrier Layer of Anodic Aluminum Oxide in Air Obtained with Scanning Tunneling Microscope

Abstract

We prepared anodic aluminum oxide (Al₂O₃) with a barrier layer. By evaporating Pt–Pd thin films on the barrier layer, surface images of several barrier layers were obtained even in air using a scanning tunneling microscope. From STM images, we found that the barrier layer consists of many domains. The measured size of domains agreed well with the estimated values from SUM photographs, though the depth of the domain walls depends on the thickness of the evaporated Pt–Pd film.