When in former times the classical III-V semiconductors namely were GaAs, GaP, InP and InAs nowadays
the research field is extended to new materials like nitrides and magnetic semiconductors and outstanding
growth mechanisms like the self-organized growth of quantum dots. In this wide range we concentrate on the
growth and optical in-situ monitoring as well as the characterisation of nearly all kind of III-V
semiconductors with Metal Organic Vapor Phase Epitaxy. The approach is to use different optical
spectroscopy methods like RAS, SE,
FTIR, and reflectometry in the gaseous ambient of MOVPE to characterise
and analyse the growth mechanisms and surface reactions. This can be done via direct comparison to UHV-experiments
on the same material classes where an access to the structural properties is given by methods like LEED, RHEED,
Auger; STM, Raman spectroscopy, etc.
Four main topics are under investigation, giving room for diploma theses:
In the SFB296 the mechanisms of self organised quantum dot growth are
highlighted for the material systems InAs/GaAs and InGaN/GaN.
Basic material property characterisation is also done, mainly in the
III-nitrides, where an upcoming discussion about the real InN bandgap
in 2001 led to an enormous progress in the growth and determination of
the material properties of InN, InGaAlN and InGaN.
For optical fibre communication lasers are needed in the wavelength
region of 1,3 and 1,55 µm. Here diluted nitride semiconductors like
GaAsN and InGaAsN are more than only promising. Their optical
properties depend strongly on the growth conditions which leads to
high level of interest for our in situ growth studies. The aim is to
improve the nitrogen content which determines the emission wavelength.
Finally the growth of ferromagnetic semiconductors as well as diluted
magnetic semiconductors (DMS) will be investigated in the near future
with respect to the formation of magnetic nanostructures and their
magneto optical properties (MOKE). Here we first focus on the
possibility of the formation of these alloys.
Contact:
- Wolfgang Richter, Markus Pristovsek (General Coordination)
- Florian Poser (III-V semiconductors, Quantum dots, GaAsN)
- Stefan Weeke (III-V semiconductors, Mn-arsenides, antimonides)
- Massimo Drago, Torsten Schmidtling (GaN, InN, GaInN)
