Impact of Thin CuGa Layers Added at the Rear Interface of Cu2ZnSnSe4 Solar Cells

In this work, the addition of CuGa layers at the rear interface of Cu 2 ZnSnSe 4 solar cells is investigated as a promising strategy to improve morphological properties of the interface and to potentially create a back electron reflector through the formation of a thin CuGaSe 2 layer. This study shows a beneficial effect of the addition of thin CuGa layers on the different photovoltaic parameters with a remarkable efficiency increase, and preliminary evidences that they might be either creating a back surface field or having a passivation effect.