Scanning tunneling microscopy and photoemission spectroscopy studies of clean and adsorbate-covered semiconductor surfaces

"Scanning tunneling microscopy (STM), photoemission spectroscopy, and a variety of other experimental techniques have been used to examine both the initial stages of interface formation between various adsorbates, as well as, reconstructions occurring on the clean surfaces of Si and Ge. The initial stages of oxidation of the Si(111)-(7 x 7) and Ge(111)-c(2 x 8) surfaces were studied. Images of the same area of each surface were obtained from various exposures of oxygen. On the Si(111)-(7 x 7) surface, the results show that defect sites act as nucleation centers for the oxidation process. On the Ge(111)-c(2 x 8) surface, images of the surface for exposures of oxygen up to 1600 Langmuirs were obtained. The results show that the oxidized portions of the surface grow as islands which expand preferentially in the (112) direction. The ""16 structure"" and c(8 x 10) reconstructions occurring on the clean Ge(110) surfaces were examined. STM images show that the Ge(110)-""16 structure"" reconstructed surface is composed of ordered facets as predicted by a low-energy-electron diffraction study. STM images of the Ge(110)-c(8 x 10) surface show that the unit cell is composed of alternating oblique sub-unit cells. Photoemission spectra of the Ge 3d core levels for both these surfaces show the presence of multiple surface-shifted components. Sb deposition on these surfaces has also been studied. Sb deposition results in the formation of a (1 x 1) or (3 x 2) ordered over-layer depending on the substrate temperature and Sb coverage. Both these surfaces have been observed with STM. Photoemission results for various coverages of Sb show that the surface-shifted components of the Ge 3d core level are suppressed by the deposition of Sb. A structural model, consistent with the data, for the (1 x 1) Sb-terminated surface is presented. Angle-resolved photoemission spectroscopy was used to measure the bulk band-dispersion relations along the high symmetry $\Gamma$-$\Sigma$-X directions for both Ge and Si."

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics, Condensed Matter

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Leibsle, Frederick Michael

Contributors dc:contributor

• Chiang, Tai-Chang

• Physics, Condensed Matter

Statement dc:rights

• Copyright 1991 Leibsle, Frederick Michael

Language dc:language

eng

Identifier

AAI9136653
(UMI)AAI9136653

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/23753