Current status of bottom-up fabrication approaches for Cu(In,Ga)Se2 micro-concentrator solar cells

Cu(In,Ga)Se-2 solar cells have reached a record efficiency of 23.35% and are established as a renewable energy technology. However, future large-scale fabrication might he hindered by the availability and high cost of raw materials. To reduce the amount of solar cell material, strong efforts have been devoted to the development of the micro-concentrator photovoltaics concept for Cu(In,Ga)Se-2 thin-film solar cells, which combines the well stablished concentrator photovoltaics (CPV) technology with the miniaturization of the solar cells. In this work, we review different bottom-up approaches for the fabrication of Cu(In,Ga)Se-2 micro solar cells, that potentially allow the reduction of raw materials, and we present the latest results on a magnetron sputtering based method for Cu(In,Ga)Se-2 micro solar cells.