Optoelectronic materials doped with Er atoms are receiving widespread attentions due to their impact on optical communication systems operating at 1.54 mu m. Optical amplifiers based on Er-doped fibers have demonstrated major improvements in link distance, data rates and reduced needs for signal regeneration. III-V semiconductors doped with Er offer the prospect of very stable, temperature-insensitive, laser diodes emitting at 1.54 mu m. This paper provides a review of the luminescence characteristics of III-V semiconductors doped with Er atoms. Aspects of Er incorporation in the III-V crystal host, photoluminescence properties, and prototype electroluminescent devices are addressed. Details of some of the first observations of photoluminescence of Er atoms in III-V nitride semiconductors, in particular GaN epilayers, are discussed. The GaN epilayers were optically excited using an argon-ion laser and spectra, centered at 1.54 mu m, were observed at 6, 77 and 300 K. The spectra display many of the allowed transitions typical of the Er3+ configuration and are nearly as intense at room temperature as at 77 K. This result indicates that the wide bandgap III-V semiconductors may be ideal host materials for Er-doped electroluminescent devices.