In this study, we investigated the effect of manganese (Mn) doping on the grain size and electrical properties of Zn1‐xMnxO films grown on c ‐sapphire substrates by plasma‐assisted molecular beam epitaxy (PAMBE). Compared with the Raman spectra of reference ZnO films grown at the same conditions without Mn‐doping, the Mn related mode is observed and studied. The surface morphology and grain size were investigated by atomic force microscopy (AFM). The results show that the grains become smaller with increasing the Mn doping content. The electric properties including carrier concentration and mobility have been studied by Hall measurements. The decrease in mobility and the increase in resistivity of the samples with higher Mn doping content might be related to an increase of impurity scattering centers. The electric properties of the grain interior and grain boundary have been studied by using impedance spectroscopy (IS). Based on the IS data, we found that the relaxation time increases gradually with increasing Mn doping content. Besides, the activation energy for grain and grain boundary conduction are studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The effects of (NH4)2Sx treatment on the surface electronic properties of the thin indium tin oxide (ITO)-doped ZnO films have been examined in this study. Experimental results, found that the formation of S-metal bonds and the removal of oxygen vacancies near the (NH4)2Sxtreated ITO-doped ZnO surface could lead to an increase in the surface energy and the work function, meaning that (NH4)2Sx treatment might be more helpful to form the uniform deposition of the organic semiconductor on ITO-doped ZnO surfaces and improve the efficiency of ZnO-based organic devices.