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2008
Journal Article
Titel
Surface passivation schemes for high-efficiency n-type Si solar cells
Abstract
An effective passivation on the front side boron emitter is essential to utilize the full potential of solar cells fabricated on n-type silicon. However, recent investigations have shown that it is more difficult to achieve a low surface recombination velocity on highly doped p-type silicon than on n-type silicon. Thus, the approach presented in this paper is to over-compensate the surface of the deep boron emitter locally by a shallow phosphorus diffusion. This inversion from p-type to n-tpe surface allows the use of standard technologies which are used for passivation of highly' doped n-type surfaces. Emitter saturation current densities (J(0c)) of 49 fA/cm(2) have been reached with this approach on SiO2 passivated lifetime samples. On solar cells a certified conversion efficiency of 21.7% with an open-circuit voltage (V-oc) of 676 mV was achieved.