Positron Annihilation Lifetime Measurements and Ab-initio Calculations on Al-doped ZnO Semiconductor

L. C. DAMONTE; G. N. DARRIBA; M. RENTERÍA

Leuven

Conferencia; International Conference on Hyperfine Interactions and their Applications; 2016

Zinc oxide is a II-VI semiconductor suitable in numerous technological applications such as optoelectronic devices, solar cells, gas sensors, etc. It is well known that the addition of different dopants, both as acceptors or donors, improve its performance. Powder mixtures of ZnO and Al2O3 in adequate proportion yielding different contents of Al (5, 10 and 30 at/vol % were prepared by mechanical milling. The systems were characterized by X-ray diffraction (XRD) and positron lifetime measurements. The annihilation parameters evolution with milling time allows us to verify the dopant incorporation into the ZnO wurtzite structure or the formation of new phases. The equilibrium structures were obtained applying the Full-Potential Augmented Plane Waves plus local orbitals (APW+lo) method, embodied in the WIEN2k code, which combined with the MIKA program give us the characteristic semiconductor lifetimes. Also, from the ab-initio electronic structure calculations, the density of electronic states (DOS) was obtained as a function of the dopant concentration. Both theoretical and experimental results are compared in order to get insight into the structural and electronic properties of the doped semiconductor and their influence on devices performance.