AVS 57th International Symposium & Exhibition
    Energy Frontiers Topical Conference Thursday Sessions
       Session EN+SS+TF-ThA

Paper EN+SS+TF-ThA2
Relationship Between Resistivity Stability and Structure of Transparent Conducting Impurity-doped ZnO Thin Films

Thursday, October 21, 2010, 2:20 pm, Room Mesilla

Session: Transparent Conductors
Presenter: J.-I. Nomoto, Kanazawa Institute of Technology, Japan
Authors: J.-I. Nomoto, Kanazawa Institute of Technology, Japan
T. Hirano, Kanazawa Institute of Technology, Japan
T. Miyata, Kanazawa Institute of Technology, Japan
O. Ueda, Kanazawa Institute of Technology, Japan
T. Minami, Kanazawa Institute of Technology, Japan
Correspondent: Click to Email
Recently reported results show that the resistivity stability for moisture-resistance and heat-resistance tests in transparent conducting impurity-doped ZnO thin films prepared on low temperature glass substrates is considerably affected by the film thickness as well as the kind and content of doped impurity. In this paper, we discuss the relationship between the obtainable resistivity stability and the structure in Al-, Ga- and B-doped ZnO (AZO, GZO and BZO) thin films prepared with a thickness in the range from 30 to 3000 nm by various deposition methods. Transparent conducting AZO, GZO and BZO thin films were prepared on glass substrates at 200oC by dc or rf magnetron sputtering, vacuum arc plasma evaporation and pulsed laser depositions. The resulting film structures were evaluated using a scanning electron microscope (SEM), an atomic force microscope (AFM) and a transmission electron microscope (TEM). The surface morphology of the impurity-doped ZnO films was found to change significantly after exposure to a highly moist environment (air at 85% relative humidity and 85oC) for 1000 h, as evidenced from AFM and SEM images; although the resistivity stability in these tests tended to improve with increasing impurity-doped ZnO thin film thickness, the effect was considerably dependent on the kind of doped impurity. In contrast, the surface morphology changed only slightly even after exposure to an oxidizing atmosphere (air at a temperature of 200oC) for 1000 h. The resistivity stability in the heat-resistance tests was found to depend significantly on whether the testing temperature was lower or higher than approximately 300oC. The amount of resistivity increase in the moisture-resistance and heat-resistance tests was found to correlate with the structure of the impurity-doped ZnO thin films, as evidenced from TEM images. The variation exhibited in the resistivity stability in these resistance tests is mainly attributed to micro-structural differences associated with the crystallinity of the deposited impurity-doped ZnO thin films.