硅片及其太阳电池的光衰规律研究

Study on light-induced degradation of silicon wafers and solar cells

采用氙灯模拟太阳光源,将光强调至1000 W/m2,研究常规太阳能级单晶硅片、多晶硅片和物理提纯硅片的原片、去损减薄片、热氧化钝化片、双面镀氮化硅(SiN x:H)膜钝化片、碘酒钝化片以及太阳电池的光衰规律.利用WT-2000少子寿命测试仪以及太阳电池I-V特性测试仪分别对硅片的少子寿命和太阳电池的I-V特性参数随光照时间的变化进行了测试.结果表明:所有硅片以及太阳电池在光照的最初60 min内衰减很快随后衰减变慢,180 min之后光衰速率变得很小,几乎趋于零.

In this paper, the laws of light-induced degradation （LID） in silicon wafers and solar cells are investigated by using xenon lamp as light source. There are tested 15 types of the silicon wafers contain the including primary wafer, chemical thinned wafer, thermal oxidation passivation wafer, passivation SiNx ： H wafer deposited by plasma enhanced chemical vapor deposition, iodine passivation wafers of three different types of silicons： B-doped CZ-Silicon, B-doped Multicrystalline （MC） silicon, and B-doped Upgraded-Metallurgical-grade （UMG） silicon. There are tested 3 types of silicon solar cells： CZ solar cell, MC solar cell, and UMG solar cell. The light intensity is 1000 W/m2 in test. By using WT-2000 tester and solar cells I-V tester, the variations of minority carrier lifetimes of silicon wafers and the I-V characteristic parameters of solar cells with time of light exposure are tested and recorded. Finally the law of LID is found. Under our light condition （light source is a xenon lamp with a light intensity of 1000 W/m2）, all kinds of silicon wafers and solar cells are degraded rapidly within the first 60 min, then slowly until the 180 min, finally the rate tends to 0. The LID becomes very slight after 180 min lighting.