Standard Deviation Quantitative Characterization and Process Optimization of the Pyramidal Texture of Monocrystalline...

To quantitatively characterize the pyramidal texture of monocrystalline silicon cells and to optimize the parameters of the texturing process, the relative standard deviation S_h was proposed to quantitatively characterize the uniformity of the pyramidal texture. Referring to the definition and calculation of the standard deviation in mathematical statistics, S_h was defined as the standard deviation of the pyramid relative height h_i after normalization of the pyramid height H_i of monocrystalline silicon wafer surfaces. Six different silicon cells, with different pyramidal textures, were obtained by applying different texturing times. The relationships between S_h and the photoelectric characteristics were analyzed. The feasibility of quantitatively characterizing the uniformity of the pyramidal texture using S_h was verified. By fitting the S_h curve, the feasibility of optimizing the texturing process parameters and predicting the photoelectric characteristics using S_h was verified. The experimental and analytical results indicate that, when the relative standard deviation S_h was smaller, the uniformity of the pyramidal texture obtained by texturing was better. The photoelectric conversion efficiency (PCE) of the silicon cells monotonically increased with decreasing S_h. The silicon cell obtained by texturing with 2% tetramethylammonium hydroxide (TMAH) solution for 18.1 min had a textured surface with a minimum of S_h, the reflectivity of the silicon cell reached its minimum value of 2.28%, and the PCE reached its maximum value of 19.76%.