Education
- 07/2002 – Doctoral degree in Physics (Dr. rer. Nat.), Univ. Bonn, Germany.
- 12/1998 – Diploma in Physics, Univ. Bonn, Germany.
Professional Employment Career
- Since 03/2008 - Auxiliary Researcher (5 years contract), ITN, Sacavém,
Portugal.
- 10/2005-02/2008 – Post-doctoral fellow at the Instituto Tecnológico e Nuclear
(ITN), Sacavém, Portugal.
- 01/1999-07/2002 – Teaching Assistant at the Univ. of Bonn, Germany
during the PhD work.
Fellowships and Training
- 10/2005-02/2008 – Post-doctoral fellow
by the Portuguese Fundação para a Ciência e Tecnologia (FCT) at ITN, Sacavém, Portugal.
- 10/2002-09/2005 – Post-doctoral fellow in the European Research & Training
Network RENIBEL (HPRN-CT-2001-00297) at ITN, Sacavém, Portugal.
- 01/1998-07/1998 – ERASMUS student, Université Claude Bernard, Lyon,
France.
Scientific Specialization
Main Scientific
Area of Research
- Main
scientific research area is the structural characterization of wide band gap
semiconductors like group-III nitrides and ZnO. One focus is the optical
doping of group-III nitrides with rare earth elements by ion implantation.
The characteristic rare earth emissions, covering a wide wavelength range
including the entire visible spectrum, render this material an interesting
choice for electroluminescent devices. Another major research field is the
structural characterization of III-nitride ternary and quaternary alloys,
and quantum dots using ion beam analysis and x-ray diffraction. In
particular, the AlInN alloy attracts research interest because of the
possibility to grow AlInN lattice matched on GaN reducing the strain and
dislocation density in (opto)electronic devices.
Scientific Work
-
Doctoral
Thesis: "Implantation studies in Group-III Nitrides". University of Bonn,
Germany (2002).
-
Diploma
Thesis: "Investigations on the diffusion of iodine in GaAs", University of
Bonn, Germany (1998).
-
Author or co-author of
more than 60 original publications in refereed journals.
-
More than 50 lectures,
oral presentations and communications to national and international
meetings.
Participation in Projects
- Member of team in the European Research and Training Network RENIBEL
(HPRN-CT-2001-00297); 2002-2005.
- Coordinator of the project "Optical doping of AlN and GaN/AlN
nanostructures by ion implantation" funded by FCT (POCI/FIS/57550/2004);
2005-2008.
- Member of team in project “Perturbed Angular Correlation Experiments at
the Portuguese Research Reactor” funded by FCT (POCI/FIS/58498/2004);
2005-2008.
- Coordinator of the bilateral project "Doping of GaN-based nanostructures
by ion-implantation" with the University of Bonn (DAAD (Germany) / GRICES
(Portugal)); 2005-2007.
- Coordinator of the project "Ternary and quaternary nitride alloys for
lattice matched heterostructures: Novel materials for high efficiency field
effect transistors and optoelectronic devices" funded by FCT (PTDC/FIS/65233/2006);
2007-2010.
- Member of team in project “Ion-implanted magnetic nanolayers of wide
band gap semiconductors for spintronics applications” funded by FCT (PTDC/FIS/66262/2006);
2007-2010.
- Coordinator of the bilateral project "Rare Earth doped GaN quantum dots
for efficient light emitters " with the CEA-Grenoble (EGIDE (France) /
GRICES (Portugal)); 2008-2009.
- Member of team in project “Experiências de Correlações Angulares
Perturbadas e de Canalização de Electrões no ISOLDE-CERN” funded by FCT (POCI/FP/81921/2007);
2007-2008.
5 Selected Publications
- "Reversible changes in the lattice site structure for In implanted into
GaN", K. Lorenz, F. Ruske, R. Vianden, Appl. Phys. Lett.
80 (2002) 4531.
- "High temperature annealing and optical activation of Eu implanted GaN",
K. Lorenz, U. Wahl, E. Alves, S. Dalmasso, R. W. Martin, K. P. O’Donnell,
S. Ruffenach, O. Briot, Appl. Phys. Lett. 85 (2004) 2712.
- "Damage formation and annealing at low temperatures in ion implanted ZnO",
K. Lorenz, E. Alves, E. Wendler, O. Bilani, W. Wesch, M. Hayes, Appl. Phys. Lett. 87 (2005) 191904.
- "High temperature annealing of rare earth implanted GaN films:
Structural and optical properties", K. Lorenz, U. Wahl, E. Alves, E. Nogales,
S. Dalmasso, R. W. Martin, K. P. O’Donnell, M. Wojdak, A. Braud, T. Monteiro,
T. Wojtowicz, P. Ruterana, S. Ruffenach, O. Briot, Optical Materials 28
(2006) 750.
- "Anomalous Ion Channeling in AlInN/GaN Bilayers: Determination of the
Strain State", K. Lorenz, N. Franco, E. Alves, I. M. Watson, R. W. Martin,
K. P. O’Donnell, Phys. Rev. Lett. 97 (2006) 85501.
- "Strain relaxation during AlInN growth on GaN", K. Lorenz, N. Franco, E. Alves, S. Pereira, I. M. Watson, R. W. Martin, K. P. O’Donnell,
J. of
Crystal Growth 310 (2008) 4058.
Invited Talks in International Conferences
-
"High
Temperature Annealing of Rare Earth Implanted GaN-Films: Structural and Optical Properties",
Spring Meeting of the European Materials
Research Society (E-MRS), Strasbourg, France, May 31 – June 3, 2005, Symposium C: Rare earth
doped photonic materials, K. Lorenz, U. Wahl, E. Alves, E. Nogales, S.
Dalmasso, R. W. Martin, K. P. O’Donnell, T. Wojtowicz, P. Ruterana, S. Ruffenach, O.
Briot. -
"RBS/Channelling analysis of GaN quantum dots in AlN Multilayers",
XVII International
Conference on Ion Beam Analysis (IBA), Seville, Spain, June 26 – July 1, 2005, K. Lorenz, N. P. Barradas,
E. Alves, D. Jalabert, B. Daudin. -
"Rare Earth implantation of III-nitride semiconductors
for light emission from IR to UV", 16th International
Conference on Ion Beam Modification of Materials (IBMM 2008), Dresden,
Germany, August 31 - September 05, 2008, K.
Lorenz, E. Alves, F. Gloux, P. Ruterana, M. Peres, T. Monteiro, K. Wang, I. S.
Roqan, E.
Nogales, R.W. Martin, K.P. O’Donnell.
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