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

Chapter 6
MBE Growth of InAs and InGaAs
Quantum Dots Embedded in GaAs
Matrix
6.1 Overview
The hetroepitaxial growth of GaAs on Si has been investigated to provide heterogeneous
substrates including both Si and III-V semiconductor layers [91, 92, 93].
In this chapter, new approaches or methods to integrate GaAs with silicon substrate
will be investigated. The rst approach is basically based on self-assembled
eects of MBE growth of InAs QDs on the top of GaAs islands using islands mechanism
growth on at silicon substrate. The advantage to use GaAs as barrier prior
to InAs quantum dots growth is the reduced lattice mismatch of ∼ 7% compared
to Si matrix of about ∼ 11%. Moreover, this approach provide also the possibility
to increase the distance between the Si/InAs interface by a GaAs spacer layer,
and gradually reducing the strain energy prior to the active layer growth. A further
approach is based mainly on the growth of GaAs/InGaAs/GaAs structure
on pre-patterned Si substrates. However, the hetroepitaxial growth of III-V QDs
directly on at silicon substrates has proven to be very challenging due to the
defects formation caused by dislocations and anti-phase domains, which originate
from the large lattice and thermal expansion mismatch and polar/non-polar
nature of III/V and Si systems [1, 2, 94]. These structural defects are closely
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