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

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

Leuven

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

HFI/NQI Executive Committee

 Zinc oxide is a II-VI semiconductor suitable innumerous technological applications such as optoelectronic devices, solarcells, gas sensors, etc. It is well known that the addition of differentdopants, both as acceptors or donors, improve its performance. Powder mixturesof ZnO and Al2O3in adequate proportion yielding different contents of Al (5, 10 and 30 at% wereprepared by mechanical milling. The systems were characterized by X-raydiffraction (XRD) and positron lifetime measurements. The annihilationparameters evolution with milling time allows us to verify the dopantincorporation into the ZnO wurtzitestructure or the formation of new phases. The equilibrium structures wereobtained applying the Full-Potential Augmented Plane Waves plus local orbitals(APW+lo) method, embodied in the WIEN2k code, which combined with the MIKAprogram give us the characteristic semiconductor lifetimes. Also, from the ab-initio electronic structurecalculations, the density of electronic states (DOS) was obtained as a functionof the dopant concentration. Both theoretical and experimental results arecompared in order to get insight into the structural and electronic propertiesof the doped semiconductor and their influence on devices performance.