IFLP   13074
INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Experimental and ab initio study of Ta-doped ZnO semiconductor
Autor/es:
E. L. MUÑOZ; D. RICHARD; P. D. EVERSHEIM; M. RENTERÍA
Lugar:
CERN, Ginebra, Suiza.
Reunión:
Conferencia; HFI/NQI2010, 15th International Conference on Hyperfine Interactions & 19th International Symposium on Nuclear Quadrupole Interaction; 2010
Institución organizadora:
Comite organizador de la reunión
Resumen:
In the last  years, ab initio calculations performed in the framework of the Density Functional Theory (DFT) have been successfully applied to the study of doped oxide semiconductors. The Full-Potential Augmented Plane Wave plus local orbitals (FP-APW+lo) method enables to determine the Electric-Field-Gradient tensor (EFG) at impurity sites localized in cation sites of the host structure with very good precision. From an ab initio - experimental study, the electronic structure  and structural relaxations produced by the inclusion of the Perturbed Angular Correlation (PAC)  tracers in the host system can be determined [1,2,3] . In this work, we present PAC results in  polycrystalline ZnO semiconductor implanted with (181Hfà)181Ta probes. The FP-APW+lo calculations in Ta-doped ZnO were carried out using the supercell method and varying self-consistently the charge state of the impurity. Ta is a triple donor impurity with respect  to Zn2+ in ZnO and thus it can loose 1, 2 o 3 donor electrons under certain circumstances. The comparison between the experimental EFG results and our  ab initio predictions suggests that the Ta impurity may be in a completely ionized charge state, i.e., with the 3 donor electrons removed from the impurity. References [1] Anisotropic Relaxations Introduced by Cd Impurities in Rutile TiO2: First-Principles Calculations and Experimental Support                        L.A. Errico, G. Fabricius, M. Rentería, P. de la Presa, and M. Forker. Physical Review Letters 89, 55503 (2002). [2] Metal Impurities in an Oxide: Ab Initio Study of Electronic and Structural Properties of Cd in Rutile TiO2 L.A. Errico, G. Fabricius, and M. Rentería. Physical Review B 67, 144104 (2003). [3] Metal Impurities in an Oxide: Ab Initio Study of Electronic and Structural Properties of Cd in Rutile TiO2 G. N. Darriba, L. A. Errico, P. D. Eversheim, G. Fabricius, and M. Rentería. Physical Review B 79, 115213 (2009).
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