Visible and infrared emission from Er-doped III-N light emitting diodes

We report on the visible and infrared emission characteristics of Er-doped III-N light-emitting diodes (LEDs). Quantum well-like device structures were grown through a combination of metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) on c-plane sapphire substrates. The dual stage growth process was used to take advantage of the high quality of AlGaN layers produced by MOCVD and in situ doping of Er during MBE growth. The multilayer structures were processed into devices and LEDs with different sizes and geometric shapes were produced. Electroluminescence (EL) was observed under either forward or reverse bias conditions. Visible-and infrared spectra displayed narrow emission lines representative of the Er3+ system. The temperature dependence of the spectra, which were measured from 100K to 300K, showed a stability in the visible emission intensity but a sharp decrease in the infrared intensity at room temperature. Based on light output vs current measurements, estimates of the excitation cross-section were obtained for visible EL emission.