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Brief overview of current and past research topics

Since 1985

European Center for Nuclear Physics Research, CERN, Geneva.
Leader of an experimental group at the on-line isotope separator ISOLDE at CERN.
Emission channeling studies for the lattice location of implanted impurities in semiconductor materials using radioactive isotopes.
Development of the theoretical description of electron emission channeling based on the dynamical theory of electron diffraction.

Development of emission channeling studies using the short-lived alpha emitter 8Li.

First demonstration of substitutional P in Diamond as potential n-type dopant.

Setup of an X-ray CCD sensor for energy- and time position resolve spectroscopy of energetic electrons.

1986-1987   

Participation in measurements of radioactive fallout following the reactor accident at Chernobyl and in environmental studies.

I gave several seminars on the consequences of the reactor accident and was advisor for several city and community administrations.

1988-1989   

Post-Doc at the University of North Carolina at Chapel Hill.

Development of the Elastic Recoil Coincidence Technique for multi-element depth profiling of light elements using He ion beams.

Since 1993   

Investigation of growth processes of diamondlike thin film materials, carbon based materials and cubic boron nitride(c-BN) using mass selected ion beam deposition.
Development of the cylindrical thermal spike model for the formation of diamondlike film properties.
Synthesis of ta-C/Si heterojunction diodes
Investigation of the phase formation of carbon nitride, boron carbide and fluorinated amorphous carbon during ion beam deposition
First demonstration of room temperature growth of c-BN
First demonstration of c-BN heteroepitaxy on AlN
First demonstration of c-BN growth by B and N ion implantation
Introduction of a phase diagram for ion beam synthesis of boron nitride thin films

First demonstration of self-organized multilayer formation during ion beam synthesis of metal carbon nanocomposite materials
Synthesis of BN/ZnO heterojunction diodes by ion beam deposition
Investigation of metal/carbon nano-composite thin films and analysis of self-organized multilayer formation processes
Synthesis and analysis of Metal- Amorphous Semiconductor -Semiconductor (MASS) hetero-junction diodes

Since 1997   

Photoluminescence studies of ion-implanted impurities in wide band gap semiconductors
Demonstration of intense UV luminescence in Gd doped AlN
Investigation of rare earth luminescence in cubic boron nitride
Crystal field analyses and lattice location studies of rare earth elements in GaN and AlN
Observation of boron bound excitons in B implanted diamond
Identification of the I9 photoluminescence line in zinc oxide

Since 1998   

Investigation of ion track effects after swift heavy ion irradiation of materials
Investigation of the formation and application of conducting ion tracks in diamond-like amorphous carbon (tetrahedral amorphous carbon, ta-C)
Electrical characterization of conducting ion tracks
Fabrication of field emission devices based on conducting ion tracks
Investigation of swift heavy ion induced annealing of GaN
Construction and set-up of the equipment for the M3-beamline at GSI for swift heavy ion irradiation of materials and in-situ analysis techniques.
Ion beam modification and tuning of electrical properties of metal-insulator transition materials (ZrO2)

Highly conducting ion tracks  in ta-C by 30 MeV C60 ion irradiation

Higlhy conducting ion tracks in ta-C:Cu by 1 GeV 238-U ion irradiation

Since 2000   

Investigation of nanoscale surface pattern formation by ion beam erosion
Systematic investigation of pattern formation on Si and carbon materials.
Demonstration of a correlation between surface structure and magnetic texture after ion beam erosion of ferromagnetic films
Development of “surfactant sputtering” (simultaneous co-deposition of impurity atoms) as steady state process  for surface pattern formation, surface smoothing, shaping of surfaces and ultra-thin film formation.

Demonstration of phase separation as relevant process for pattern formation during surfactant sputtering

 

Since 2003   

Setup of ion beam techniques at the Göttingen 3MV tandem accelerator and the 500 kV ion implanter
Development of a high-resolution (1nm) RBS system using an electrostatic analyzer
Development of a Monte Carlo program for analysis of high resolution RBS spectra.
Renewal of the Nuclear Reaction Analysis beamline for hydrogen depth profiling
Setup of a proton micro beam for µ-PIXE analysis and proton beam writing
Proton beam writing and mask free lithography of semiconductor materials

Since 2007   

Development of a full digital spectrometer for coincidence gamma-spectroscopy and angular correlation gamma spectroscopy
Modeling and simulation of scintillation detectors for gamma radiation

Analysis of MAX-phase ternary compounds using gamma-gamma angular correlation spectroscopy

Since 2010

Development of a new versatile ion implantation chamber for ISOLDE/CERN

Since 2013

Ultra low energy (< 25 eV) ion implantation doping of graphene with B, N, F, etc.



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