Research On Textured Monocrystalline Silicon Solar Cells

Pyramidal textured monocrystalline silicon wafers can reduce thereflectivity of light down to below10%,therefore enhance theproduction of the solar cells. The dissertation studies the influencingfactors of forming pyramidal textured structure,and obtains theconditions for forming the uniform complete textured structure. Thedissertation also studies the way of light propagating over the surface ofthe textured monocrystalline silicon solar cell and the way of optimizingthe surface of the textured monocrystalline silicon to further improve theconversion efficiency of the solar cell.Alkali solution can etch differentcrystal faces of monocrystalline silicon by different velocity, which cantextured the surface of monocrystalline silicon wih pyramidal structure.The dissertation shows changing the concentration of NAOH andisopropyl alcohol can change the rate of etching on the surface ofmonocrystalline silicon and then influence the forming of pyramidalstructure. The etching rate being too high or too low cannot form theuniform valid textured structure. The proper etching rate can result inthe best textured surface.Textured monocrystalline silicon solar cells withlow reflectivity is because light propagate though the textured surfacewith two times of reflection, which resulting the lower reflectivity thanwih one time of reflection. The dissertation demenstrates the opticalprinciples.The last part of the dissertation shows the way of optimizingthe fore surface of the textured monocrytalline silicon solar cell by SiNxfilm deposited by PECVD and the way of smoothing the back surfaceby wet-chemical oxidation and removing the oxidized Si atoms andetching the back surface by alkali.