Low cost anisotropic etching of monocrystalline Si (1 0 0): Optimization using response surface methodology Khuram Ali ⇑ , Sohail Aziz Khan, Mohd Zubir Mat Jafri Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia article info Article history: Received 31 March 2012 Received in revised form 20 May 2012 Accepted 17 June 2012 Available online 28 June 2012 Keywords: Tetramethyl ammonium hydroxide Optimized surface texturing Response surface methodology Silicon solar cells abstract Reduced surface reflectance and enhanced light trapping is required by any high efficiency solar cell. Anisotropic etching was done on silicon (100) by using tetramethyl ammonium hydroxide TMAH, (CH 3 ) 4 NOH, solution at 85 °C. Process variables considered were solution concentration and time proposed by response surface methodology (RSM). An effective surface texture was resulted with reflectance less than 8% without antireflection coating. The antireflection mechanism was also co-related with the etch rate of Si. Optimized values predicted by RSM for time and TMAH concentration were 5 min and 3.50% respectively. The technique and optimization of parameters by using response sur- face methodology (RSM) could be valuable in the texturization pro- cess for high-efficiency Si solar cells. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Pyramid formation is a standard technique for reducing the reflectance and to enhance the short circuit current in single-crystalline Si solar cells [1]. It can be achieved by plasma etching, mechanical engraving, and electrochemical etching [2–4]. But anisotropic wet chemical etching with TMAH aque- ous solution is broadly accepted as a commercial standard method due to its cost efficiency, ease of use, no physical damage introduced to the bulk [5,6] and uncontaminated metal ions which are desir- able for high performance solar cells [7,8]. Surface texturing is used in crystalline Si wafers to increase the path length of incident light and to maximize light absorption into Si solar cells [1,9,10]. Light trap- ping also allows a significant reduction in the thickness of active solar cell material and especially in 0749-6036/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.spmi.2012.06.008 ⇑ Corresponding author. Tel.: +60 149037205. E-mail address: khuram_uaf@yahoo.com (K. Ali). Superlattices and Microstructures 52 (2012) 782–792 Contents lists available at SciVerse ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices