晶体硅和无定形硅的区别.pptVIP

* 晶体硅与无定形硅 Crystalline Silicon High efficiency in IR only Expensive Ages quickly Amorphous Silicon Lower efficiency (no IR) Shows little aging Inexpensive Tandem cells of Micro-crystalline and amorphous Silicon High efficiency (including IR) Shows no aging Economical Solar Panels Morphology Characterization Crystalline Silicon Band Amorphous Silicon Band Pure Crystalline Silicon 晶体硅与无定形硅 Amorphous Silicon: Blue Microcrystaline Silicon: Red 晶体硅与无定形硅 Applications of Raman Spectroscopy * Another area getting a lot of attention with Raman recently is the analysis of crystalline and amorphous Silicon in solar panel devices. Crystaline Silicon results in panels with high efficiency in the IR only. They are expensive and unfortunately they suffer degradation with exposure to light. Amorphous silicon results in devices with lower efficiency as they do not respond to IR frequencies, however they are relatively inexpensive and they show little degradation with exposure to light. More recently there have been cells developed using microcrystalline and amorphous Silicon. This combination offers the best of both worlds. They are high efficiency – responding to IR frequencies. They show virtually no degradation with exposure to light and they are still economical. New slide in spring 2008 Applications of Raman Spectroscopy * Another one of the useful aspects of Raman is that Raman can be a good discriminator based on molecular morphology. This is because the bonds that are represented the strongest in the Raman spectrum tend to be the symetrical bonds of the molecular backbone. These bonds are typically impacted to a greater extent by morphological changes than are the end functional groups that are best represented in the IR. Any change in morphology is going to result in at least some of the backbone molecular bonds being positioned at different angles. In the case of amorphous and crystaline silicon, the change is actually quite dramatic as we illustrate here. T