Seung-Hong Kim

Effects of Electron Irradiation on the Properties of ZnO Thin Films

ZnO films were deposited on glass substrates by radio frequency (RF) magnetron sputtering and exposed to intense electron beam irradiation to investigate the effects of electron irradiation on the properties of the films. Although all of the films had ZnO (002) textured structure regardless of electron irradiation, the grain sizes of the films decreased with electron irradiation. Surface roughness also depended on electron irradiation. The surface roughness varied between 2.3 and 1.6 nm, depending on the irradiation energy. Based on photoluminescence (PL) characterization, the most intense UV emission was observed from ZnO films irradiated at 900 eV. Since the intensity of UV emission is dependent upon the stoichiometric of ZnO films, we conclude that 900 eV was the optimum electron irradiation energy to achieve the best stoichiometric of ZnO films in this study.

Effect of Vacuum Annealing on the Properties of ITO Thin Films

Abstrart ITO thin films deposited on glass substrate with RF magnetron sputtering were vacuum annealed at 100, 200 and 300C for 30 minutes and then effect of annealing temperature on the structural, electrical and optical properties of ITO films were investigated. The structural properties are strongly related to annealing temperature. The annealed films above 100C are grown as a hexagonal wurtzite phase and the largest grain size is observed in the films annealed at 300C. The electrical resistivity also decreases as low as 4.65 × 10 Ωcm with a increase in annealing temperature and ITO film annealed at 300C shows the lowest sheet resistance of 43.6 Ω/ □ . The optical transmittance in a visible wavelength region also depends on the annealing temperature. The films annealed at 300C show higher transmittance of 80.6% than those of the films prepared in this study. (Received January 28, 2013; Revised February 13, 2013; Accepted February 20, 2013)

The Influence of Al Underlayer on the Optical and Electrical Properties of GZO/Al Thin Films

100 nm thick Ga doped ZnO (GZO) thin films were deposited with DC and RF magnetron sputtering at room temperature on glass substrate and Al coated glass substrate, respectively. and the effect of the Al underlayer on the optical and electrical properties of the GZO films was investigated. As-deposited GZO single layer films had an optical transmittance of 80% in the visible wavelength region, and sheet resistance of 1,516 , while the optical and electrical properties of GZO/Al bi-layered films were influenced by the thickness of the Al buffer layer. GZO films with 2 nm thick Al film show a lower sheet resistance of 990 , and an optical transmittance of 78%. Based on the figure of merit (FOM), it can be concluded that the thin Al buffer layer effectively increases the performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.