Unusual bismuth-containing surface layers of III-V compound semiconductors
Ahola-Tuomi, Marja (2013-06-15)
Turun yliopisto Annales Universitatis Turkuensis A I 463.
15.06.2013
Kuvaus
Siirretty Doriasta
Tiivistelmä
The understanding and engineering of bismuth (Bi) containing semiconductor surfaces
are signi cant in the development of novel semiconductor materials for electronic
and optoelectronic devices such as high-e ciency solar cells, lasers and light
emitting diodes. For example, a Bi surface layer can be used as a surfactant which
oats on a III-V compound-semiconductor surface during the epitaxial growth of IIIV
lms. This Bi surfactant layer improves the lm-growth conditions if compared
to the growth without the Bi layer. Therefore, detailed knowledge of the properties
of the Bi/III-V surfaces is needed. In this thesis, well-de ned surface layers
containing Bi have been produced on various III-V semiconductor substrates. The
properties of these Bi-induced surfaces have been measured by low-energy electron
di raction (LEED), scanning-tunneling microscopy and spectroscopy (STM), and
synchrotron-radiation photoelectron spectroscopy. The experimental results have
been compared with theoretically calculated results to resolve the atomic structures
of the studied surfaces. The main ndings of this research concern the determination
of the properties of an unusual Bi-containing (2×1) surface structure, the discovery
and characterization of a uniform pattern of Bi nanolines, and the optimization of
the preparation conditions for this Bi-nanoline pattern.
are signi cant in the development of novel semiconductor materials for electronic
and optoelectronic devices such as high-e ciency solar cells, lasers and light
emitting diodes. For example, a Bi surface layer can be used as a surfactant which
oats on a III-V compound-semiconductor surface during the epitaxial growth of IIIV
lms. This Bi surfactant layer improves the lm-growth conditions if compared
to the growth without the Bi layer. Therefore, detailed knowledge of the properties
of the Bi/III-V surfaces is needed. In this thesis, well-de ned surface layers
containing Bi have been produced on various III-V semiconductor substrates. The
properties of these Bi-induced surfaces have been measured by low-energy electron
di raction (LEED), scanning-tunneling microscopy and spectroscopy (STM), and
synchrotron-radiation photoelectron spectroscopy. The experimental results have
been compared with theoretically calculated results to resolve the atomic structures
of the studied surfaces. The main ndings of this research concern the determination
of the properties of an unusual Bi-containing (2×1) surface structure, the discovery
and characterization of a uniform pattern of Bi nanolines, and the optimization of
the preparation conditions for this Bi-nanoline pattern.
Kokoelmat
- Väitöskirjat [2275]