Electric field gradient calculations in ZnO samples implanted with 111-In(111-Cd)
ABSTRACT A first-principles study of the electric field gradient (EFG) calculated for ideal and 111In(111Cd) implanted ZnO samples is reported in the present work. The study was made for ZnO ideal hexagonal structures and supercells were introduced in order to consider the possible implantation environments. The calculation was done using the “WIEN2k” code within the density functional theory, the exchange and correlation effects were determined by the GGA approximation. Three possible 111In(111Cd) implantation configurations were studied, one substitutional incorporation at cation site and two interstitials. The obtained EFG values for the ideal structure and the substitutional site are in good agreement with the experimental reports measured by perturbed angular correlation (PAC) and high precision nuclear magnetic resonance (NMR). Thus, the ascription of substitutional incorporation of 111In(111Cd) probe atom at the ZnO cation site after annealing was confirmed.
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ABSTRACT: Local environments in 0.5 at.% In-doped ZnO were investigated by means of the time-differential perturbed angular correlation (TDPAC) method. In a comparative study, using the 111Cd probe nuclei as the decay products of different parents, 111In and 111mCd, we found that 111In microscopically forms a unique structure with nonradioactive In ion(s) dispersed in ZnO, whereas 111mCd has no specific interaction with the In impurities. The spectral damping of the TDPAC spectra is attributed to the aftereffect following the EC decay of 111In. It was demonstrated from the aftereffect that the local density and/or mobility of conduction electrons at the 111In probe site in the In-doped ZnO is lowered due to the characteristic structure locally formed by the dispersed In ion(s).Physical review. B, Condensed matter 12/2012; 86(23). · 3.66 Impact Factor