Epitaxial N-type silicon solar cells with 20% efficiency

Silicon wafers have still a significant contribution to the total cost of production for silicon solar cells. One cost driver when using classical wafering techniques is kerf loss. With the approach using porous silicon as a detachment layer and as a seed layer for epitaxy kerf losses can be avoided. In this work, solar cells with epitaxially grown n-type wafers are presented. The best EpiWafer-cell reaches an open circuit voltage of 657.5 mV, a short circuit current of 39.6 mA/cm ² and a fill factor of 77%. The resulting energy conversion efficiency of 20% proves the high quality of this material.