Structuring the Surface of Thin Si Solar Cell by Metal Assisting Etching for Efficient Light Trapping

Prof. Rasit TuranCenter for Solar Energy Research and Applications (GÜNAM), METU Ankara, Turkey

Prof. Rasit Turan
Center for Solar Energy Research and Applications (GÜNAM), METU Ankara, Turkey.

By Prof. Rasit Turan, Center for Solar Energy Research and Applications (GÜNAM) and Department of Physics, Middle East Technical University, Ankara, Turkey.

Photovoltaic solar cell conversion technologies are attracting increasingly higher attention due to recent developments in cost reduction and improved conversion performance. In particular, crystalline Silicon (Si) cell technology has reached an extremely well maturity level with well-optimized material and process conditions. However, for an ultimate victory of solar energy over other energy resources, further improvements in the cell efficiency and reduction the cost are needed. Such developments should be based on new approaches employing new material and device structures. Among such efforts, use of thinner wafers are attracting special attention for a potentially significant reduction in the material cost. However, for thin Si wafer ( Micro- and nano-structures including well aligned nanowires can be formed by a technique based on Metal assisted Etching (MAE) which is a solution based electrochemical etching process taken place on Si surface. The structural properties of the surface can be tailored using appropriate chemical solutions and process parameters. In this work, we have employed MAE technique to fabricate various surface structures and shown that they can provide effective light trapping properties. We have also fabricated solar cells with thick and thin wafers showing the effectiveness of the MAE for surface texturing even for industrial size solar cells. It has then become clear that MAE technique is suitable and promising technique for surface structuring at industrial scale.


Raşit Turan completed B. Sc. and M. Sc. degrees at the Physics Department of Middle East Technical University (METU), Turkey. He received his Ph.D degree from University of Oslo, Norway in 1990. He worked as Post. Doc. at Linköping University, Sweden. He joined METU Physics Department as faculty member in 1991. He worked as a visiting scientist at the Material Science Department of Toronto University, Canada in 1996. His main research interests have been physics and technology of semiconductor materials and devices including solar cells. He has published more than 160 scientific papers in this field in the internationally recognized journals. He has supervised 7 Ph.D. and about 20 M.Sc. studies.

Rasit Turan has coordinated many national and international projects. Among them, European FP6 projects SEMINANO, and METU-CENTER have been among the largest research and support projects coordinated by Dr. Turan. I 2009, he founded a new research center called Center for Solar Energy Research and Applications (GUNAM) on METU campus. GUNAM has attracted nationwide and international attention. Recently, a national solar energy system development project, called MILGES, been given to the consortium where GÜNAM is a key member for solar cell development.