Erbium-doped GaN epilayers synthesized by metal-organic chemical vapor deposition

GaN is an excellent host for Er due to the low thermal quenching of radiative intra-4f Er³⁺ transitions at 1.54 μm. Thus, Er doped GaN structures are promising for emitters and amplifiers operating at the main telecommunication wavelength of 1.54 μm. We report on the experimental study and synthesis of Er doped GaN by metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) with above and below bandgap excitation energies were employed to study the optical properties of Er doped GaN. PL spectra of these Er doped layers exhibit a strong 1.54 μm emission, corresponding to the intra-4f transition of the ⁴I_13/2 (first excited state) to the ⁴I_15.2 (ground state) of Er³⁺. Secondary ion mass spectroscopy (SIMS) and x-ray diffraction (XRD) of the Er doped GaN shows the films to be of high crystalline quality with a high Er concentration (2-3 × 10²¹ cm^-3) and low impurity concentrations. The mechanisms of optical transitions involving different excitation energies, and potential applications of Er doped GaN structures in the communication wavelength are also discussed.