Silicon being the dominant material used in semiconductor industry, the demonstration of reliable control of electron spin ensembles in Si compatible structures represents a milestone towards a commercial application of all-semiconductor spintronic devices. Due to intrinsic properties of bulk Si this demonstration has proven to be challenging until very recently. This project aims at the demonstration of spin injection and transport in Si based thin films as well as at the exploration of the underlying physical phenomena. A key element will be the use of carrier confinement with Germanium quantum dots in Si and Silicon-Germanium quantum wells, giving access to an optical probing of electron spins. In a second focus we will characterize self-assembled Germanium Manganese nanomagnets in a Si matrix. Nanomagnetism studied in semiconductor matrices offers an interesting approach to understand the properties of magnetic semiconductors as well as the possibility of efficient spin injection into Si.