Full metadata
Title
Conversion of a molecular beam epitaxy system for the growth of 6.1 angstrom semiconductors
Description
A dual chamber molecular beam epitaxy (MBE) system was rebuilt for the growth of 6.1 Angstrom II-VI and III-V compound semiconductor materials that are to be used in novel optoelectronic devices that take advantage of the nearly continuous bandgap availability between 0 eV and 3.4 eV. These devices include multijunction solar cells and multicolor detectors. The MBE system upgrade involved the conversion of a former III-V chamber for II-VI growth. This required intensive cleaning of the chamber and components to prevent contamination. Special features including valved II-VI sources and the addition of a cold trap allowed for the full system to be baked to 200 degrees Celsius to improve vacuum conditions and reduce background impurity concentrations in epilayers. After the conversion, the system was carefully calibrated and optimized for the growth of ZnSe and ZnTe on GaAs (001) substrates. Material quality was assessed using X-ray diffraction rocking curves. ZnSe layers displayed a trend of improving quality with decreasing growth temperature reaching a minimum full-width half-maximum (FWHM) of 113 arcsec at 278 degrees Celsius. ZnTe epilayer quality increased with growth temperature under Zn rich conditions attaining a FWHM of 84 arcsec at 440 degrees Celsius. RHEED oscillations were successfully observed and used to obtain growth rate in situ for varying flux and temperature levels. For a fixed flux ratio, growth rate decreased with growth temperature as the desorption rate increased. A directly proportional dependence of growth rate on Te flux was observed for Zn rich growth. Furthermore, a method for determining the flux ratio necessary for attaining the stoichiometric condition was demonstrated.
Date Created
2012
Contributors
- Dettlaff, W. Hank G (Author)
- Zhang, Yong-Hang (Thesis advisor)
- Vasileska, Dragica (Committee member)
- Johnson, Shane (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
ix, 76 pages : illustrations (some color)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.14897
Statement of Responsibility
by W. Hank G. Dettlaff
Description Source
Viewed on March 19, 2013
Level of coding
full
Note
thesis
Partial requirement for: M.S., Arizona State University, 2012
bibliography
Includes bibliographical references (pages 72-76)
Field of study: Electrical engineering
System Created
- 2012-08-24 06:25:23
System Modified
- 2021-08-30 01:46:44
- 3 years 2 months ago
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