Comparison of texturing methods for monocrystalline silicon solar cells using KOH and Na/sub 2/CO/sub 3/

摘要

We investigate two chemical random texturing methods on mono crystalline silicon wafers. To simulate an industrial process 25 p-type monocrystalline silicon (10/spl times/10) cm/sup 2/ wafers are textured in one step. We compare aqueous solutions consisting of potassium hydroxide (KOH) and isopropyl alcohol (IPA) and solutions consisting of sodium carbonate (Na/sub 2/CO/sub 3/) and sodium hydrogen carbonate (NaHCO/sub 3/). The dependence of the reflectance on etching time, solution temperature and concentration is shown. We achieved weighted reflectance values as low as 12.5% and 16.5% respectively with the two solutions. Furthermore homogeneity and pyramid size are reported. Industrial type solar cells with a homogeneous emitter and screen printed contacts were processed. Efficiencies up to 16.6% with textured surfaces could be achieved for screen printed solar cells on 1 /spl Omega/cm p-type Cz silicon wafers.