Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1555334 | Superlattices and Microstructures | 2006 | 8 Pages |
Abstract
The dependence of electrical and structural properties on film thickness was studied on polycrystalline undoped zinc oxide (ZnO) thin films on glass substrates at 200Â âC prepared by plasma-assisted electron-beam deposition. The film thickness was varied from 23 to 316Â nm. Hall effect measurements for undoped ZnO films showed that while the Hall mobility increased with increasing film thickness up to almost 130 nm, it remains almost constant on further increasing the film thickness (>130Â nm). The carrier concentration changes a little. As a result, the dependence of the resistivity on film thickness was determined by that of Hall mobility. It was clarified by out-of-plane and in-plane X-ray diffraction (XRD) that while the orientation of undoped ZnO with a thickness below 130 nm is random, ZnO films with a larger thickness (>130Â nm) change to c-axis orientation. In-plane XRD line broadening analysis, using the Williamson-Hall method, reveals that both the crystallite size and remaining microstrain increase with increasing film thickness. The same tendency of the averaged surface roughness (Ra), from atom force microscopy (AFM) measurement, as that of the structural and physical properties described above was observed.
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
S. Kishimoto, T. Yamamoto, Y. Nakagawa, K. Ikeda, H. Makino, T. Yamada,