A single electron spin confined to a quantum dot is one of the most explored physical realisations for a quantum bit (qubit). So far, experimental work has focused on GaAs-based quantum dots, but an EU-funded project looked into an alternative material system.
The EU-funded project SPIDERMAN (Electronic transport and spin dynamics through SiGe self-assembled quantum dots) focused on silicon-germanium (SiGe) self-assembled quantum dots. In both Si and Ge, electrons' spins can have a long coherence time due to small hyperfine interaction.
Further details: Self-assembled quantum dots