| Summary: | 碩士 === 國立中山大學 === 光電工程學系研究所 === 104 === In this study, we fabricate heteorjunction solar cells which are composed of P-type cuprous oxide on N-type silicon wafer. First, the silicon wafer was textured with KOH alkaline solution to lower the weighted reflection. In the following, we used thermal oxidation to grow silicon oxide on the surface of silicon wafer, and removed the grown oxide with wet etching. There are two reasons to do so. One is to lower the sharpness of pyramid structure, and another is to remove particles which could attach to the silicon surface during fabricating process. Moreover, we do the surface passivation of silicon using supercritical fluid to repair defects. Finally, we deposited P-type cuprous oxide on silicon substrate with both solution process and reactive sputtering and completed the devices by fabricating the metal electrodes. The reflectivity of silicon substrate was reduced from 29.6% to 15.3% by texturizing the Si surface. The SEM pictures also showed that the sharpness of pyramid structure was successfully reduced with thermal oxidation and etching. However, this led to an increase of reflectivity. The reflectivity increased from 15.3% to 17.7% after removing 0.5μm thermal oxide on the Si surface. Finally, the performance of devices was measured by solar simulator at AM1.5. The best devices showed an open circuit voltage (VOC ) of 0.3V、a short circuit current density (JSC) of 1.03mA/cm2、a full factor (FF) of 0.37 and an energy conversion efficiency (η) of 0.11%. The carrier lifetime of the textured silicon wafer which is passivated with supercritical fluid is only 94.1μs. The carrier lifetime must be improved before a high performance Cu2O/n-Si heterojunction solar call can be obtained.
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