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

Introduction
1.1.2 Thesis Approach
The successful integration of the III-V materials on silicon holds a great promise
for the future demonstration of the practical integrated III-V optoelectronic devices
on a Si CMOS platform. In particular, optical interconnect systems provide
a promising approach for the realization of the next generation high-speed communication
and computing technologies [11]. However, compatibility with microelectronic
fabrication technologies is very limited. Our 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 or by embedding the active layer (III-V quantum dots or
dashes nanostructures) in III-V matrix using the minimum amount of III-V materials
as a barrier, i.e., below the critical thickness as it is illustrated in Fig. 1.1.
This is most likely possible by utilizing the large strain accommodation properties
of nanostructured III-V materials. However, the luminescence eciency of
an indirect bandgap matrix can be dramatically improved by inserting a narrow
and a direct bandgap material like InAs or InGaAs in silicon matrix. 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]. On the other
Figure 1.1: Schematic diagram of the thesis approach under the BMBF project (MON-
ALISA), where the III-V semiconductor are just limited to the active layer and embedded
in Si matrix or embedded in thin III-V matrix as a barrier.
hand, it has been proposed that these structural defects may be circumvented
4