This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/27735
Description
Title
Electroreflectance of germanium
Author(s)
Koeppen, Stephen Howard
Issue Date
1971-02
Doctoral Committee Chair(s)
Handler, Paul
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
electroreflectance
germanium
band structure
Language
en
Abstract
The band structure of germanium in the energy region .7 eV to 5 eV was investigated using the electroreflectance (ER) technique. Several transitions were detected in this energy range and in almost all cases, the associated critical points were identified as to their type and origin in k-space. At the direct edge (r~ r7 transitions at .79 eV), interference between the degenerate light and heavy hole band contributions to the lineshape was observed and a good fit to the sum of two one-electron lineshapes for a 3-dimensional M critical point was obtained. A good fit to the 3-D M theory was also obtained for the spin orbit split structure (r7 ~ r7 transitions at 1.08 eV) and was used as a means of determining the electric field. A doublet structure at 2.1-2.3 eV was shown to agree extremely well with the 2-dimensional M critical point theory. In addition, effects due to band-filling were observed when the energy bands were bent into accumulation. These results indicate that the transitions responsible for this structure occur over an extended region of the Brillouin zone, including the L-point.
Structure was also observed near 3 eV and 4 eV but the large amount of lifetime broadening prevented any detailed quantitative analysis. The 4 eV structure, however, was characteristic of a single 3-D M1-transverse critical point and the broadening of this structure was estimated to be 120 meV. A set of experimental conditions necessary for making reliable ER measurements which agree with the uniform-field, one-electron theory, was developed and used throughout the experiment. These included: (1) modulation from the flat-band condition, (2) the use of high fields to minimize many-body effects, and (3) the use of uniform fields by proper choice of sample doping levels and modulation conditions.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
