Ga2O3-ZnO composite coaxial nanotubes have been fabricated via a simple process combining thermal reaction and physical evaporation. The resulting nanotubes are either empty or partially or completely filled with Ga (see Figure), forming Ga (core)-Ga2O3 (interlayer)-ZnO (outer shell) three-layer coaxial nanocables. The photoluminescence of the nanostructures is investigated and a mechanism for their formation is proposed.