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

Chapter 1
Introduction
Modern semiconductor microelectronics technology is mainly based on silicon
as a key material, several advantages of silicon such as the very good electrical
properties, high thermal conductivity, cheapness and the large scale availability
made silicon the best candidate among other semiconductor materials in the
current microelectronics industry. However, silicon has a very poor optical emission
properties due to it is indirect band gab, and of very weak non-linearities,
which is needed for optical switches, LEDs, lasers etc applications. In contrast,
III-V materials are the dominate materials in today optoelectronics market due
to their very excellent optical properties, because of their high eciency optical
transitions, which originate from their direct fundamental band gap energy.
The monolithic integration of the III-V on silicon holds a great promise for the
future demonstration of the practical integrated III-V optoelectronic devices on a
Si complementary metal oxide semiconductor (CMOS) platform as well as it will
shift the optoelectronic market from using very expensive substrates like GaAs
and InP to Si substrates. However, the heteroepitaxial growth of III-V quantum
dots (QDs) directly on silicon substrates has proven to be quite challenging due
to the defects caused by dislocations and anti-phase domains, which originate
from the large lattice and thermal mismatches and polar/non-polar nature of
III/V and Si systems [1, 2]. These structural defects are closely related to carrier
dynamics in the QDs and have severe inuence on their optical quality. So far,
only few details on the growth mechanism of InAs and InGaAs nanostructures
on at silicon substrates have been provided in literature [3, 4]. However, in this
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