Research of Surface Passivation on Silicon Solar Cells
|Course||Detection Technology and Automation|
|Keywords||Crystalline silicon solar cells Heavily doped surface passivation Back passivation A silicon nitride film Annealing characteristics|
The use of photovoltaic cell power generation is an important way to solve the energy and environmental problems. Currently, more than 80% of the solar cell is prepared from crystalline silicon material, the preparation of high-efficiency, low-cost crystalline silicon solar cells for large-scale use of photovoltaic power generation has a very important significance. Passivated front surface and a back surface passivation is a very important process for the preparation of high efficiency crystalline silicon solar cells, surface passivation of solar cells directly determine the minority carrier lifetime of the level of detection of minority carrier lifetime surface passivation of crystalline silicon solar cells, we carried out a systematic experimental study. In the Summary of this laboratory on the basis of highly efficient solar cell passivation techniques for the heavily doped surface passivation in Chapter passivated by thermal oxidation of a variety of conditions (including the oxidation temperature, oxidation time) on the solar cell front surface passivation effect. Analysis by detecting minority carrier lifetime as well as the parameters of the electrical properties of the open-circuit voltage, in screening a large number of experimental results can be found in the 840 ° C around the oxidation temperature and oxidation time of about 10 minutes to ensure good surface blunt effects. Under such conditions, the production process, can be affected by high temperature in the oxidation process, the silicon wafer down to a lesser extent, also to ensure a better antireflection effect and the passivation effect. In the fourth chapter, the back of the solar cell silicon nitride film passivation, the same through the detection of minority carrier lifetime, the ordinary thermal annealing characteristics of silicon nitride film and rapid thermal annealing characteristics, and on the back of the silicon nitride The experimental film passivation battery. Experimental study by conventional thermal annealing, a silicon nitride film is more suitable for the annealing temperature of 500 ° C or less, and SiN / SiO2 bilayer membrane stability than the SiN film, it is more suitable for at 600 ° C to -700 subjected to an annealing temperature of between ℃. After high-temperature annealing above 800 ° C, the SiN film and SiN / SiO2 bilayer membrane surface passivation effect basically lost. Experimental study of rapid thermal annealing found can get a better surface passivation effect SiN film rapid thermal annealing at 700 ° C -850 ° C, annealing at high temperature (900 ° C and temperature) is the best choice for high belt speed . By experiments carried out on a silicon nitride film on the back passivation battery, using screen printing technology to form 300um aperture point contact electrode spacing of 2 mm, the open circuit voltage can reach 628mv provides the necessary basis for the further realization of the back passivation.