Title:	Material Study on ZnO/Ag Back Reflectors for Silicon Thin Film Solar Cells
Author(s):	J. Hüpkes, T. Wätjen, R. Van Aubel, R. Schmitz, W. Reetz, A. Gordijn
Keywords:	Microcrystalline-Silicon, Sputtering, Back Reflector, Zinc Oxide
Topic:	Thin Films
Subtopic:	Amorphous and Microcrystalline Silicon
Event:	23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session:	3AV.2.24
Pages:	2419 - 2421
ISBN:	3-936338-24-8
Paper DOI:	10.4229/23rdEUPVSEC2008-3AV.2.24
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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We studied the absorption losses in the back ZnO layer as well as the influence of surface structure of the ZnO/silver interface on silicon thin film solar cell properties. Low absorption is one crucial factor for reflector performance. Thus, addition of oxygen to the sputter gas might be necessary to optimize reflector performance. Additionally, light scattering at the back reflector is still important, even if light scattering is already introduced by the front contact. This is demonstrated by comparison of polished and conformal silver reflector interface. Finally we indicate further potential by improvement of the silver reflectivity by high temperature growth of silver reflector. However, due to limitation of the maximum substrate temperature by the silicon p-i-n structure this improvement cannot be easily transferred to cell efficiency.