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The interaction of Na impurities and O vacancies (VO) in ZnO was studied in theory and experiment. The VO facilitated substitutional Na (NaZn/NaZn-) acceptors with inhibiting interstitial Na (Nai/Nai+) donors, which may benefit the p-type conductivity. The formed (NaZn-VO)+/0 complexes induced the change of band structures of ZnO, with the broadening of gap energies and disappearance of the VO2+-related impurity level, which confirmed by the blue shift of the near-band-edge (NBE) UV emission and the decay of the visible emission in PL spectra. The strong and dominant NBE UV emission suggested acceptable luminescence behaviors of Na-doped ZnO. [ABSTRACT FROM AUTHOR]

Dislocations in the ZnMgO pleated nanosheets were observed from high-resolution transmission electron microscopy (TEM). The Burgers vector was identified as [formula] from the Fourier filtered TEM images. Raman spectra revealed that there were microstructure defects in the ZnMgO nanosheets with the increasing Mg content. The incorporation of the Mg impurities in the ZnMgO nanosheets may promote the congregation of oxygen vacancies and thus facilitate the generation of dislocations. The oxygen deficiency as well as surface dislocations played an important role in determining the optical properties of ZnMgO pleated nanosheets. [ABSTRACT FROM AUTHOR]

Li-doped ZnO films were prepared by pulsed laser deposition. The carrier type could be controlled by adjusting the growth conditions. In an ionized oxygen atmosphere, p-type ZnO was achieved, with the hole concentration of 6.04 × 1017 cm-3 at an optimal Li content of 0.6 at. %, whereas ZnO exhibited n-type conductivity in a conventional O2 growth atmosphere. At a Li content of more than 1.2 at. % only high-resistivity ZnO was obtained. The amount of Li introduced into ZnO and the relative concentrations of such defects as Li substitutions and interstitials could play an important role in determining the conductivity of films. [ABSTRACT FROM AUTHOR]

We report on intrinsic p-type ZnO thin films by plasma-assisted metal-organic chemical vapor deposition. The optimal results give a resistivity of 12.7 Ω cm, a Hall mobility of 2.6 cm2/V s, and a hole concentration of 1.88×1017 cm-3. The oxygen concentration is increased in the intrinsic p-type ZnO, compared with the n-type layer. Two acceptor states, with the energy levels located at 160 and 270 meV above the valence band maximum, are identified by temperature-dependent photoluminescence. The origin of intrinsic p-type behavior has been ascribed to the formation of zinc vacancy and some complex acceptor center. [ABSTRACT FROM AUTHOR]