Photoemission study of Mg/PTCDA/Se-GaAs Schottky contacts

Citation
S. Park et al., Photoemission study of Mg/PTCDA/Se-GaAs Schottky contacts, APPL SURF S, 175, 2001, pp. 249-254
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
APPLIED SURFACE SCIENCE
ISSN journal
0169-4332 → ACNP
Volume
175
Year of publication
2001
Pages
249 - 254
Database
ISI
SICI code
0169-4332(20010515)175:<249:PSOMSC>2.0.ZU;2-O
Abstract
The influence of a very thin PTCDA interlayer on the chemical and electroni c properties of Mg/Se-CaAs(1 0 0) Schottky contacts was investigated using soft X-ray photoemission spectroscopy (SXPS). The PTCDA molecules preferent ially adsorb at defect sites. Upon Mg deposition a strong intermixing occur s and leads to the formation of MgSe irrespective of the presence of a PTCD A interlayer. The PTCDA interlayer delays the appearance of the metallic Mg feature due to the formation of MgO as a result of the reaction between Mg and PTCDA. The strongest effect of the interlayer on the electronic proper ties occurs below a Mg coverage of 2.3 monolayer (ML). The rate at which th e Schottky barrier height reaches the final value is slower in the presence of the PTCDA interlayer, which is consistent with the delay of the appeara nce of metallic Mg. In addition, it is found that the submonolayer coverage of PTCDA prevents the Mg induced surface states observed at the submonolay er coverage of Mg on Se/GaAs(1 0 0) surfaces. (C) 2001 Elsevier Science B.V . All rights reserved.