A method is provided for depositing a transparent conductive oxide (TCO) layer on a substrate, in which contaminations of the layers of the layer system is reduced through the diffusion of material from the substrate, and whose layer properties in respect to coupling and transmission of light are optimized. For that purpose, a barrier layer, a seed layer and a transparent conductive oxide layer are directly successively deposited on the substrate. Also, a thin-film solar cell is described which comprises such a transparent conductive oxide layer.