In the work described here, a vapor transport method and corresponding in situ oxidation−reduction reaction are used in order to introduce GeOx into Er-doped SnO2 nanofibers for the deliberate purpose of producing a carrier-mediated excitation enhancement pathway into a conducting host. It is demonstrated that the photoluminescence intensity of Er-doped SnO2 nanofibers at 1540 nm can be enhanced via a carrier-mediated mechanism by almost two orders of magnitude after the introduction of this germanium suboxide. Furthermore, with proper fabrication conditions, Ge nanorods can be prepared on the surface of these SnO2 nanofibers.