| Abstract |
| Influences of surface oxygen plasma treatment on the work function of ITO thin films were studied. As a result of plasma etching, the roughness of the film was reduced with increasing plasma treatment time. The REELS measurement with primary electron energy of 300eV revealed that the band gap of the extreme surface of the thin film was increased by 1.03eV. At 1700eV, however, the band gap of the film remained unchanged. The UPS results indicated that the work function increased by 0.82eV and from the XPS spectra the valence band maximum was measured to be 5.32eV after the plasma treatment. The change in the work function of the extreme surface of the film was attributed to an increase in the amount of oxygen after the plasma treatment, which did not affect the electrical conductivity or the value of the band gap. XPS was used to examine whether the oxygen plasma treatment caused any change in the composition ratio of the ITO thin film. The spectra showed that almost all of the peaks for the carbon compounds of C-H-O were eliminated after the plasma treatment. In addition, In-O bonds and O=O bonds were increased as a result of abundant oxygen in the surface of the film. Our results demonstrated that the electronic, optical, and structural properties of plasma-treated ITO thin films in an oxygen environment were greatly improved. |
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| Key Words |
| surface modification, indium tin oxide, ITO, reflected electron energy loss spectroscopy, REELS, wltra violet photoelectron spectro scopy, UPS, x-ray photoelectron spectroscopy, XPS |
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