INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Positron Annihilation Lifetimes Calculation in ZnO and Al-doped ZnO semiconductors
S. FERRARI; L. C. DAMONTE
Workshop; 4th Workshop on Novel Methodsfor electronic structure calculations, and first southamerican congress on materials; 2011
The addition of small quantities of dopant on zinc oxide nano-particles modifies their optical and electrical properties. In particular, the electron densities sensed by Positron Annihilation Lifetime Spectroscopy (PALS) may change according to dopant charge and localization in the host crystalline structure. In this sense, calculation of positron annihilation parameters can be useful in order to a better comprehension of experimental results. In this work, positron annihilation lifetimes on pure and Al-doped ZnO calculations are presented. Calculations were performed by two different methods: (A) using non-self-consistent electron densities and electrostatic potentials obtained by atomic superposition method (ATSUP) and (B) using densities and potentials obtained by self-consistent calculations of the electronic density within the framework of Projector Augmented Wave method (PAW). The calculations were done both in non-relaxed and relaxed structures. At the light of the present theoretical results positron lifetime experimental measurements on milled Al-doped ZnO nanosize powders are analyzed.