Development of electronic band structure of the K-adsorbed Si(111)7 × 7 surface

Autor: G E Frank-Kamenetskaya, D. V. Daineka, G V Benemanskaya
Rok vydání: 1999
Předmět:
Zdroj: Journal of Physics: Condensed Matter. 11:6679-6684
ISSN: 1361-648X
0953-8984
DOI: 10.1088/0953-8984/11/35/306
Popis: Adsorption of K on the Si(111)7 ? 7 surface has been investigated in the submonolayer coverage range at room temperature. The method of threshold photoemission spectroscopy using s- and p-polarized light excitation was employed for studying the evolution of surface electronic structure near the Fermi level, the work function and the ionization energy. A qualitative change in character of band structure has been observed, depending on K coverage. Suppression of metallicity of the Si(111)7 ? 7 surface was found at the initial stage of K adsorption. One surface band A1 below the VBM was revealed at low coverage. Increasing K coverage has led to both the appearance of the K-induced band A2 and significant movement of the band towards the Fermi level. The K/Si(111)7 ? 7 interface was found to be semiconducting-like up to saturation coverage. Near saturation, the Fermi level is seen to cross the K-induced band A2. Such surface band structure is identified as being metallic-like. Results indicate metallization via adlayer accompanied by Fermi level pinning.
Databáze: OpenAIRE