Preparation and characterization of homogeneity and fine pyramids on the textured single silicon crystal

Abstract

Texturing of silicon surface is a major way to increase short circuit current and then improve the efficiency of silicon solar cells by effective light trapping.The anisotropic texturing of a (100) silicon surface was performed using tetramethyl ammonium hydroxide (TMAH) solution and NaClO additive in combination with continual ultrasonic wave treatment.The effect of ultrasonic wave and NaClO on the nucleation and growth of finc pyramids during the anisotropic texturing, and the effect of size of pyramids on the minority carrier lifetime of textured silicon wafer after the high temperature process were investigated.The enhancement of homogeneity of the smaller pyramids in the textured structure of silicon crystalline is obtained by adding continnal ultrasonic wave treatment to control the time of H2 bubble staying on the silicon surface and the speed of H2 detaching from the surface.The weighted mean reflectance for the solar spectrum AM 1.5G is 12.4% for the silicon surface with the optimal size of pyramids.After high temperature oxidation, the size of pyramid has an obvious exponential relation with the minority carrier lifetime of textured silicon wafer.