| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 106 === Potential induced degradation (PID) is an important reliability issue in the silicon-based solar energy technology. This problem greatly degrades the photoconversion efficiency of the solar cell module and, in the worst case, results in the overall failure of the solar cell system. This thesis discusses the causes of the PID effect and focuses modification methods alleviating the effect.
The study is divided into two parts. First, we adjusted the gas flow ratio of the gas precursor (SiH4/NH3) to study the influence of the ratio on the film quality of the silicon nitride (SiNx) anti-reflection coating layer, which can alleviate the PID effect by retarding sodium ions from diffusing from the glass panel to the solar cell module. From the study, a high SiH4/NH3 flow rate ratio improves the chemical structure of the nitride film, resulting in a better performance in blocking the migration of foreign sodium ions and thus a improved resistance against the PID effect.
In the second study, we modify the device structure of the Si-base solar cell by depositing a thermal silicon oxide layer between the Si wafer and the anti-reflection layer. forming a Si/ SiO2/ SiNx multilayer structure. The thickness of the oxide layer was about 10 nm according to TEM analysis. Because of the oxide layer, positive fixed oxide charges are present at the interface and forms a potential barrier retarding the invasion of external sodium metal ions from the solar cell packaging materials into the solar cell modules. As a consequence PID effect can be greatly reduced by the addition of the thermal oxide layer.
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