Galvanic processes on silicon surfaces in alkaline fluoride-free solutions containing Cu(II) ions were investigated in this work. Deposition of copper (I) oxide (Cu2O) and copper metal at pH 14 onto silicon surfaces at room or elevated temperatures has been demonstrated. This deposition does not require the presence of a reducing agent in the solution. The results clearly show that Cu(II) ions can be reduced to Cu(I) or Cu(0) by silicon and, as a consequence, Cu2O or copper metal can be deposited at the surface of the substrate. (C) The Author(s) 2016. Published by ECS. All rights reserved.