Samples of Er and O co-doped InGaAs/GaAs multiple quantum-well structures were grown by means of low-pressure organometallic vapor-phase epitaxy, and were investigated with regard to their luminescence. The multiple quantum-well structures were designed to emit light at 0.98µm for the direct excitation of Er ions. Degradation of the structures, due to the introduction of Er and O, was not observed in X-ray diffraction patterns. Samples with Er ions, and doped with O, exhibited a sharp and well-ordered photoluminescence spectrum which arose mainly from one kind of Er center (Er-2O). Photoluminescence excitation measurements of multiple quantum-well Er,O and Er,O co-doped GaAs samples revealed that, under below-bandgap excitation (830 to 940nm), the Er-related luminescence was observed only in the multiple quantum-well Er,O sample. This indicated that the luminescence originated from Er ions in InGaAs quantum-wells via a trap-mediated excitation process.

Er-Related Luminescence in Er,O-Codoped InGaAs/GaAs Multiple-Quantum-Well Structures Grown by Organometallic Vapor Phase Epitaxy. A.Koizumi, H.Moriya, N.Watanabe, Y.Nonogaki, Y.Fujiwara, Y.Takeda: Applied Physics Letters, 2002, 80[9], 1559-61