Highly resolved electric force microscopy of metal-®lled anodic alumina

A nanowire-®lled membrane of porous anodic alumina is resolved by noncontact electric force microscopy. On nearly completely ®lled matrix areas, hillocks of about 50 nm diameter are observed. From the imaging of the tip-sample capacitance they could be identi®ed as the endings of protruding Ag wires. Some are covered with matrix residues of about 10 nm diameter which could be resolved in the capacitance image. Sample parts with smaller ®lling amounts show that phosphoric acid enlarges the pore diameters. We conclude that the wire diameters appear to be smaller than the inner pore diameters. # 2001 Elsevier Science B.V. All rights reserved.