Semiconductor on metal adsorption: Ge tetramers on the Ag 001/ surface

This paper presents an experimental study of the first stages of the growth of a semiconductor Ge.deposited at room temperature on an oriented metallic surface Ag 001... It is achieved by using scanning tunneling microscopy STM., Auger electron spectroscopy AES., low energy electron diffraction LEED.and photoelectron spectroscopy PES.. This work shows particular stable entities of four Ge atoms tetramers.which are observed as early as the first stages of growth 0.1 ML. in coexistence with isolated Ge atoms inserted in substitutional sites of the Ag top layer. These tetramers order in a p 262=462.R458 superstructure at half monolayer 0.5 Ge ML.. Beyond this coverage, the adlayer disorders. The PES study reveals the metallic character of the Ge adlayer at least up to 0.5 ML. q2000 Elsevier Science B.V. All rights reserved