Japan Society of Applied Physics;The Japan Society of Applied Physics
摘要:
摘要： Al-doped ZnO (AZO) films were prepared on a glass substrate using a magnetron sputtering system. The metallic aluminum and ZnO targets were bombarded by radio frequency power source. The Al-dopant concentration of the films, analyzed by energy-dispersive spectroscopy, increased with increasing RF power. The electrical resistivity of the films, measured by four-point probe, revealed a decrease from $3.43 \times 10^{-2}$ to $3.29 \times 10^{-3}$ $\Omega$ cm with increasing Al-content from 0.85 to 4.34 at. %. The crystal structure analyzed by grazing incidence X-ray diffraction indicated that all of the films prepared by sputtering with RF power preferred a stronger texture on (002) orientation than those with DC power applied to Al target. The optical transmittance, measured by UV--visible, indicated an average transmittance higher than 82% for all the films in visible region, and increased with Al-content; however, it reversed at 4.34 at. %. The band gap of the films increased from 3.39 to 3.58 eV with increasing RF power. Ultraviolet photoelectron spectroscopy (UPS) analysis revealed that a characteristic peak at approximately 5--7 eV was found in the AZO films due to the O 2p valence electrons. Meanwhile, the work functions of the undoped ZnO film and various AZO films were measured by UPS decreased from 4.9 to 4.5 eV with increasing Al-content. The chemical composition of the films was analyzed by X-ray photoelectron spectroscopy with Gaussian-resolved fitting. According to XPS analysis of O 1s for the films, we inferred that the decrease in electrical resistivity of the film with increasing Al-dopant concentration was predominated by the concentration of oxygen vacancies. 出版者： The Japan Society of Applied Physics 出版日期： 2013-02-01 出處： Japanese Journal of Applied Physics, 2013-02, Vol.52 (2), p.025801-025801-8 資源來源： Institute of Physics Journals 版權： licence_http://creativecommons.org/publicdomain/zero 識別號： ISSN: 0021-4922 識別號： EISSN: 1347-4065 識別號： DOI: 10.7567/JJAP.52.025801
