Laboratory-scale electronic devices can now be fabricated with atomic-scale precision via the deterministic placement of individual donor atoms in silicon, and electron spins localized on donor atoms in semiconductors form excellent two-level quantum systems (qubits) for quantum technological devices. The creation of such devices can be achieved by combinations of conventional fabrication, ion implantation, and scanning tunnelling microscopy-based fabrication. In this talk, I will present recent work in our group investigating dopants and dopant structures in silicon and germanium using low temperature STM and momentum resolved photoelectron spectroscopy.