| Summary: | 碩士 === 清雲科技大學 === 電子工程所 === 98 === In this thesis, we investigated the use of MOCVD (Metal Organic Chemical Vapor Deposition) for the growth of triple-junction concentrated GaAs solar cells. First of all, we built up a model of concentrated triple-junction GaAs solar cell concentrated model. The epitaxial thickness of the base layer in the top cell was adjusted improve the open circuit voltage (Voc), It was found that the open-circuit voltage was maximized (Voc=2.93V) when the Top Cell Base Layer thickness was 6500A, and the conversion efficiency reached 34.06%.
Then the buffer layer material was replaced with InGaAs, and the open circuit voltage dropped to 2.47V, but the maximum output voltage (Vm) was raised by 0.08V. The series resistance (Rs) value fell to 0.127 ohm, and the conversion efficiency reached 35.53%.
Finally, the thickness of the buffer layer was adjusted to find out the best thickness, which minimized the roughness of buffer layer and the lattice mismatch between nucleation layer and substrate. We found that when the buffer layer thickness was 1.4μm, the lattice mismatch is minimum, and we obtained the maximum short circuit current, and the lowest series resistance. In addition, the conversion efficiency reached 36.81 %(500 suns).
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