Our research addresses new semiconductor materials and new spectroscopic methods for their characterization. For quantum information processing, we develop new tools based on magnetic resonance which allow to manipulate and detect the spin state of quantum bits via electrical transport measurements. As qubits, we in particular study the nuclear spins of ionized donors, which based on our pioneering work have been demonstrated to have coherence times of the order of an hour at room temperature, by far exceeding any other solid-state-based qubit system.