| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系 === 96 === Indium tin oxide (ITO), one of the transparent conductive films that have been widely applied, has been known for its high conductivity and optical transmittance. Researches on ITO were mostly focused on the influence of process parameters on the conductivity and optical transmittance and, however, seldom on its thermoelectric characteristic like the Seebeck coefficient. In this research glass substrates coated with an ITO layer by means of D.C. magnetron sputtering were deposited with a tin layer of various thicknesses by means of ion beam sputtering. The thermoelectricity of ITO films coated with a tin layer of various thicknesses and annealed at 250 ℃ for 1 hr was studied. X-ray diffraction was used to analyze the crystal structure and the field-emission scanning electron microscopy inspected the surface and cross-sectional morphology. X-ray photoelectron spectroscopy is used to determine the film composition. The optical transmittance, electric resistance, Hall Effect, and Seebeck coefficient were measured. It was found in XRD patterns that all samples possess In2O3 structure. This reveals that In diffuses out from ITO film, reacts with oxygen together with the coated tin layer and a high tin ITO forms. The ITO film coated with a tin layer has higher electrical resistivity than the ITO film just annealed. In terms of thermoelectricity, the tin-coated samples show no improvement. Their Seebeck coefficient and power factor are even worse than those of the uncoated and annealed pure ITO film. In addition, it was also found that optical transmittance is greatly decreased with increasing thickness of the tin layer. However if the thickness of the tin layer continually increases to 40 nm, the optical transmission recovers to 70%. This may be caused by the reduction of surface scattering resulting from the surface smoothing.
|
|---|
