| Summary: | 碩士 === 國立東華大學 === 電機工程學系 === 103 === Gallium and aluminum co-doped zinc oxide films as the transparent electrodes for the Cu(In,Ga)Se2-based solar cells were deposited on the Corning EAGLE XG glass substrates with a ceramic GAZO target, whose composition of the target in weight percentage of ZnO:Ga2O3:Al2O3 is 96.53:2.26:1.21. The effects of sputtering parameters including the working powers, substrate temperatures, working pressures, and film thickness on the crystalline structures, morphologies, electrical properties, and optical transmittance of as-deposited films were studied.
X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV/VIS/NIR spectrometer, atomic force microscope, and 3D surface profiler were employed to characterize the crystallinity, surface and cross-sectional morphology, optical transmittance, surface roughness, and thickness of the films, respectively. In addition, the electrical properties including resistivity, mobility, and carrier concentrations of GAZO films were characterized by using Hall measurement.
The results showed that the crystallinity of GAZO films was improved by the increase of the working powers and substrate temperatures, and hence the electrical properties. The optimal electrical and optical properties of GAZO films were obtained under the working pressure of 0.4 mTorr. Besides, the optical transmittance of at least 87 % in the visible range for the as-deposited films was obtained. For the given deposition conditions, the GAZO film of 387 nm in thickness possessed a low resistivity of 4.53×10-4 Ω-cm and high optical transmittance of 91.5% in visible region.
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