Multi-crystalline silicon wafers were textured by double chemical treatments,which include acid-alkali and double acid treatments.By using SEM and reflectance spectrum,detailed study of surface morphology and optical properties of different etched surfaces was carried out.The results show that a large number of grain boundary delineation and pinholes will produce when the etching rate is too fast,and the reason is also discussed.And the results of acid-alkali treatment are better than that of double acid tr...