Oxidation of preferentially (111)-oriented Au films in an oxygen plasma investigated by scanning tunneling microscopy and photoelectron spectroscopy

The effect of an oxygen plasma and a consecutive thermal treatment on the c hemical state and morphology of a gold(111) surface has been investigated b y photoelectron spectroscopy (XPS, UPS) and scanning tunneling microscopy. An initially atomically flat Au(111) surface is oxidized to a depth of abou t 4 nm in an oxygen plasma resulting in a characteristic rough surface morp hology. The oxidation of the gold surface can be unequivocally determined f rom XPS by the chemical shift of the 4f levels. After reduction of such an oxidized gold surface by a thermal treatment, its initial spectroscopic sta te is completely restored, while the resulting morphology exhibits a patter n of nanometer-sized Au islands. (C) 2001 Elsevier Science B.V. All rights reserved.