Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA

Summary
The main focus and concerns of this PhD thesis is the growth of III-
V semiconductor nanostructures (Quantum dots (QDs) and quantum
dashes) on silicon substrates using molecular beam epitaxy (MBE)
technique. The investigation of inuence of the major growth parameters
on their basic properties (density, geometry, composition, size
etc.) and the systematic characterization of their structural and optical
properties are the core of the research work. The monolithic integration
of III-V optoelectronic devices with silicon electronic circuits
could bring enormous prospect for the existing semiconductor technology.
Our challenging approach is to combine the superior passive
optical properties of silicon with the superior optical emission properties
of III-V material by reducing the amount of III-V materials to
the very limit of the active region.
Dierent heteroepitaxial integration approaches have been investigated
to overcome the materials issues between III-V and Si. However,
this include the self-assembled growth of InAs and InGaAs QDs
in silicon and GaAx matrices directly on at silicon substrate, sitecontrolled
growth of (GaAs/In 0.15 Ga 0.85 As/GaAs) QDs on pre-patterned
Si substrate and the direct growth of GaP on Si using migration enhanced
epitaxy (MEE) and MBE growth modes. An ecient ex-situ
buered HF (BHF) and in-situ surface cleaning sequence based on
atomic hydrogen (AH) cleaning at 500 ◦ C combined with thermal oxide
desorption within a temperature range of 700-900 ◦ C has been
established. The removal of oxide desorption was conrmed by semicircular
streaky reection high energy electron diraction (RHEED)