| Summary: | 碩士 === 國立中興大學 === 光電工程研究所 === 96 === One of the parameters that limit the efficiency of a thin film solar cell, especially
the a-Si and the nc-Si solar cell is the cell thickness. Although thicker film can absorb
most of the sun light, the optical generated carriers will recombine through the
numerous gap states in the film that obtain lower short circuit current and fill factor. In
the controversy, thinner film can not absorb enough sun light that also limit the short
circuit current. In this work, we utilize nanowire structure to solve the conflict between
the light absorption and the carrier transport. The designed structure has ZnO:Al
nanowire array or n-type a-Si nanowire array on the substrate. The p-i-n a-Si solar cell
structure is grown along the surface of each nanowire sequentially. Under sunlight
illumination, the light is absorbed in the axis direction of the nanowire. However, the
carrier transport is along the radial direction of the solar cell. Therefore, the long
nanowire can absorb most of the solar light. In the meantime, the thickness of the solar
cell still is thin enough for photo-generated carrier transport. The dependence of short
circuit current, open circuit voltage and fill factor to the length, diameter and density of
ZnO:Al nanowires are simulated.
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