Synthesis and optical characterization of erbium-doped III-N double heterostructures

We report on the first successful synthesis of Er-doped III-N double heterostructures (DHs) grown on sapphire substrates. AlGaN layers, with an Al concentration of ∼12%, were prepared by metalorganic chemical vapor deposition and Er-doped GaN layers by molecular beam epitaxy. The Er concentration was estimated to be ∼1018 cm−3. GaN:Er/AlGaN single heterostructures (SHs) and AlGaN/GaN:Er/AlGaN DHs were studied using photoluminescence (PL) spectroscopy. Emission lines characteristic of the GaN:Er system (green: 537 and 558 nm, infrared: 1530 nm) were observed in all samples. With UV excitation, the infrared PL from the DHs showed a marked improvement compared to the SHs. The PL intensity increased and the spectra showed less defect-related emission. The enhanced PL properties may be due to more effective confinement of electron–hole pairs in the quantum well region.