Type

Journal Article

Authors

P. Bailey
L. Koenders
Greg Hughes
Attilio A. Cafolla
L. Roberts
B. Murphy
P. Moriarty

Subjects

Physics

Topics
physics room temperature synchrotron radiation low energy electron diffraction diffraction pattern sulfur dimers silver sulfide photoelectron spectroscopy

Photoelectron core-level spectroscopy and scanning-tunneling-microscopy study of the sulfur-treated GaAs(100) surface (1994)

Abstract A study of the adsorption of sulfur on the GaAs(100) surface after in situ thermal desorption of a protective As capping layer is presented. The sulfur flux was generated by the decomposition of silver sulfide in an UHV-compatible electrochemical cell. Use of As-capped samples provided a means to study the interaction of sulfur with both the c(2×8) and (4×1) surface reconstructions. Scanning-tunneling-microscopy images of the sulfur-covered surface indicated the formation of disordered surface layers which display a diffuse (1×1) low-energy-electron-diffraction pattern. This (1×1) phase is attributed to the symmetry of the bulk structure visible through the disordered surface overlayer, caused by the adsorbed sulfur breaking the surface dimer bonds. Synchrotron-radiation core-level photoemission spectra indicate evidence of sulfur bonding to both gallium and arsenic at room temperature, but that the relative magnitude of these bonding interactions depends on the Ga/As ratio of the clean surface. Sulfur 2p photoemission spectra from the annealed surfaces show that sulfur diffuses into the topmost atomic layers as well as bonding to the surface. Annealing the sulfur-covered surface above 400 °C results in the formation of a (2×1) low-energy-electron-diffraction pattern with a dimer-row structure clearly visible in scanning-tunneling-microscopy images. Our results would suggest that the adsorption of sulfur on the c(2×8) clean surface results in dimer rows consisting of both arsenic and sulfur dimers, while only sulfur dimers are observed after adsorption on the (4×1) surface. The degree to which the clean surface band bending is altered on these respective surfaces appears to be related to the precise chemical composition of the dimer rows.
Collections Ireland -> Dublin City University -> Publication Type = Article
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools
Ireland -> Dublin City University -> Status = Published
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Science and Health
Ireland -> Dublin City University -> Subject = Physical Sciences: Physics
Ireland -> Dublin City University -> Subject = Physical Sciences
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Science and Health: School of Physical Sciences

Full list of authors on original publication

P. Bailey, L. Koenders, Greg Hughes, Attilio A. Cafolla, L. Roberts, B. Murphy, P. Moriarty

Experts in our system

1
Greg Hughes
Dublin City University
Total Publications: 29
 
2
Attilio A. Cafolla
Dublin City University
Total Publications: 26
 
3
Barry Murphy
Trinity College Dublin
Total Publications: 18