Experimental and ab initio study of Ta-doped ZnO semiconductor

E. L. MUÑOZ, D. RICHARD, P.D. EVERSHEIM, M. RENTERÍA

Ginebra

Conferencia; HFI/NQI2010, 15th International Conference on Hyperfine Interactions & 19th International Symposium on Nuclear Quadrupole Interaction; 2010

Executive Committee del 3th HFI/NQI International Conference

In the last years, ab initio calculations performed in the framework of the DensityFunctional Theory (DFT) have been successfully applied to the study of doped oxidesemiconductors. The Full-Potential Augmented Plane Wave plus local orbitals (FPAPW+lo) method enables to determine the Electric-Field-Gradient tensor (EFG) atimpurity sites localized in cation sites of the host structure with very goodprecision. From an ab initio - experimental study, the electronic structure andstructural 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, wepresent PAC results in polycrystalline ZnO semiconductor implanted with(181Hf-->)181Ta probes. The FP-APW+lo calculations in Ta-doped ZnO were carried outusing the supercell method and varying self-consistently the charge state of theimpurity. Ta is a triple donor impurity with respect to Zn2+ in ZnO and thus it canloose 1, 2 o 3 donor electrons under certain circumstances. The comparison betweenthe experimental EFG results and our ab initio predictions suggests that the Taimpurity may be in a completely ionized charge state, i.e., with the 3 donorelectrons removed from the impurity.