Expertise

Focus of research on:

Structural and chemcial properties of hybrid inorganic-organic systems
Structure and thermal stability of interfaces
Structural, morphological, and chemical properties of quantum wires and quantum dots
Formation and characterization of defects in strained epitaxial systems

Materials systems:

Low-dimensional semiconductor nanostructures:
(cooperation within the collaborative research centre SFB 951 HIOS)

Geometry of nanostructure
Materials systems:
Substrate
Hybrid inorganic-organic systems Hexaphenyl (6P) / ZnO ZnO
  Ag nanowires nanotubular dye aggregates
Quantum dots (In,Ga)N/GaN Si, Al2O3
  (In,Ga)As/GaAs
GaSb/ GaAs
(In,Ga)P/InP
CdSe/ZnSe
GaAs
Quantum wires CdTe/ZnTe
MnTe/ZnTe
GaAs
Quantum wells (Zn,Cd)Se/ZnSe
(Zn,Mn)Se/ZnSe
(Zn,Mg)Se/ZnSe
GaAs
  ZnO/(Zn,Mg)O Al2O3

 

Device structures prepared by Focused Ion Beam milling:
(cooperation with Ferdinand-Braun-Institut für Höchstfrequenztechnik Berlin)

High brightness (HB) transistors
High electron mobility (HEM) transistors
Solar cells

Nanoparticles generated via Sol-Gel synthesis:
(cooperation with KemnitzLAB, Institut für Chemie, HU Berlin)

AlF3
MgF2
Metal particles attached to AlFOH matrix

Investigation techniques:

Bright-field and dark-field diffraction contrast imaging
High-resolution transmission electron microscopy (HRTEM)
High-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) imaging
Energy-dispersive X-ray spectroscopy (EDXS)
Electron energy loss spectroscopy (EELS)
Energy-filtered transmission electron microscopy (EFTEM)
Transmission electron diffraction (TED)
Precession transmission electron diffraction (PED)
Scanning nanobeam diffraction (SNBD)
Convergent beam electron diffraction (CBED)
Large angle convergent beam electron diffraction (LACBED)

Interpretation and analysis of the experimental results:

HRTEM: Simulations using the software package Cerius, digital analysis of lattice images (DALI) (Rosenauer)
EDXS: Numerical deconvolution of concentration profile by means of non-commercial software
CBED: Simulations of diffraction images utilizing the JEMS software (Stadelmann)

Advanced sample preparation for TEM:

Focused ion beam (FIB) milling

Instrumentation:

TEM/STEM: JEOL JEM 2200FS
TEM/STEM: HITACHI H8110
Plasma cleaner: FISHIONE

Focussed ion beam system: FEI FIB Strata 201 with KLEINDIECK micromanipulator
Low-energy ion milling system: BALTEC RES010
Full equipment for mechnical TEM specimen preparation