| Transparent conductive oxide films (TCO) have a wide range of applications in manyareas such as solar cells, flat panel displays and low-emissivity glass. Conventionaltransparent conductive material ITO (In2O3:Sn) with good optical and electrical properties,but due to In resources are limited，the prices of indium are rising quickly with the increaseddemand from industry, which seriously limits its applications. ZnO-based transparentconductive film are considered as the most likely alternative to ITO because Zn is abundant,cheap, and environment friendly, more stable in hydrogen plasma.To our knowledge, F and Ga co-doped ZnO transparent conductive thin film havereported very little, our idea is to use Ga atoms to replace Zn atoms and occupy the Zn2+lattice, then use F atoms to replace O atoms and occupy O2-lattice in order to introduceexcess electrons, which will increase the conductivity of ZnO transparent conductors.In this paper, we uses laser molecular beam epitaxy (LMBE) method to growZnO,ZnO:F (FZO), ZnO:Ga (GZO) and F and Ga co-doped ZnO (FGZO) films on quartzglass substrates. We performed a systematic study of the impact of substrate temperature,oxygen pressure, RF power on the optical and electrical properties of thin films. The physicalproperties were characterized by a variety of testing methods including X-ray diffraction(XRD), UV-visible absorption spectroscopy, Hall measurement.By comparing the optical and electrical properties of ZnO, FZO, FZO, FGZO filmprepared at the same growth condition, we found that at100℃and200℃, the electricalproperties of the FGZO film are much better than ZnO, FZO, GZO with the resistivitydecreasing and the carrier concentration increasing, which can be attributed to the F and Gadonors in zinc oxide. FGZO films treated by laser annealing process show an increase ofcarrier concentration, which indicates the UV irradiation can effectively active the F dopantsin ZnO lattices. |
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