Eurisol Topical and Town Meetings, Lisboa, 15th-­‐19th October, 2012 The study of thin films and nanostructures at atomic scale using exotic
nuclear methods
M. Barbosa (1)*, J. N. Gonçalves (2), A. Redondo-Cubero (3,4), S. M. C. Miranda (3), R. Simon (5), P. Kessler
(5), M. Brandt (6), F. Henneberger (6), E. Nogales (7), B. Méndez (7), K. Johnston (8), E. Alves (3,4), R.
Vianden (5), J. P. Araujo (1), K. Lorenz (3,4), J. G. Correia (3,4)
(1) IFIMUP and IN – Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia da
Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal, (2)
Departamento de Física and CICECO, Universidade de Aveiro, Campus Universitário de Santiago, P-3810-193
Aveiro, Portugal, (3) IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional 10,
2686-953, Sacavém, Portugal., (4) Centro de Física Nuclear da Universidade de Lisboa, Avenida Prof. Gama
Pinto, 1649-003 Lisboa, Portugal, (5) Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115
Bonn, Germany, (6) Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany,
(7) Departamento de Física de Materiales, Facultad de Ciencias Físicas, Universidad Complutense, E-28040
Madrid, Spain, (8) Technische Physik, Universität des Saarlandes, 66041 Saarbrücken, Germany.
*Presenting author: [email protected]
The study of nano-materials has grown considerably in recent years due to its promising
applications in everyday life technologies. However, its relevancy relies on both tunable
properties and the large-scale integration feasibility. Great advantages can be obtained by
merging nano-structures with thin film technologies, where ion implantation is still envisaged
as an integrated part of the processes. Still, ion implantation carries along with the benefits –
universal dopant and profile tuning – intrinsic nuisances, i.e., defects and poor solubility.
Therefore, in this highly integrated new world the small scale rules both new properties and
new problems.
Willing to contribute to the better understanding of doping and processing by ion beams, we
present here two examples of studies performed with the nanoscopic Perturbed Angular
Correlation technique that probes the charge density distribution in the surroundings of
chosen radioactive nuclei, thus allowing characterizing the probe’s real environment at the
atomic scale. We have chosen the study of ZnO and CdZnO thin films – aimed to cover
luminescence wavelengths from UV to yellow – with implanted 111mCd/111Cd probe, and the
technologically relevant high –K factor Ga2O3 nano-structures and Ga2O3 pellets where Cd is
a potential p-type dopant..
For each case, we show how and to which extent the local environment of the implanted Cd is
reconstructed to the one of the host crystalline matrix as a function of annealing temperature.
We further attempt to identity local defects with first principle simulations by DFT methods.