Surface electronic structure of the root 3x root 3, root 39x root 39 and 6x6 surfaces of Ag/Ge(111): observation of a metal to semiconductor transition
2001 (English)In: Applied Surface Science, ISSN 0169-4332, Vol. 175, 237-242 p.Article in journal (Refereed) Published
Deposition of 1 monolayer (ML) of Ag on the clean Ge(1 1 1) surface, followed by annealing at 300 degreesC for 2 min, results in a sharp root3 x root3 low-energy electron diffraction (LEED) pattern. This surface transforms into a root 39 x root 39 surface, as observed by LEED, due to a tiny amount of additional Ag atoms when the temperature is below approximately -20 degreesC. The presence of the additional Ag leads to an increased filling of two partially occupied surface bands. By depositing approximately 0.2 ML of Ag on the root3 x root3 surface, it transforms into a 6 x 6 periodicity. The addition of Ag leads to an interesting transition from the metallic surfaces (root3 x root3 and root 39 x root 39) to the semiconducting 6 x 6 surface with a gap of around 0.2 eV with respect to the Fermi-level. On the 6 x 6 phase, the lower one of the partially occupied surface bands of the root3 x root3 and root 39 x root 39 surfaces seems to be entirely pulled down below the Fermi-level, while the upper one is missing. The electronic structures of the different Ag/Ge(111) surfaces an also discussed in comparison with the Ag/Si(111) surfaces. (C) 2001 Elsevier Science B.V. All rights reserved.
Place, publisher, year, edition, pages
2001. Vol. 175, 237-242 p.
Ag/Ge(111) surfaces, LEED, photoemission, ARPES
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-49236OAI: oai:DiVA.org:liu-49236DiVA: diva2:270132