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

Abstract

GaN is an excellent host for Er due to the low thermal quenching of radiative intra-4f Er³⁺ transitions at 1.54 μm. Er doped GaN structures are promising for emitters and amplifiers operating at the main telecommunication wavelength. In recent studies, Er doped III-Nitride epilayers were obtained by ion implantation, hydride vapor phase epitaxy (HVPE), metal organic molecular beam epitaxy (MOMBE), or molecular beam epitaxy (MBE). But, in-situ Er doping of III-nitride epilayers has not been achieved by metal organic chemical vapor deposition (MOCVD), mostly due to the low vapor pressure and lack of suitable, metal organic Er sources. Since n and p type III-nitride epilayers with excellent electrical properties and high crystalline quality are easily achieved by the MOCVD method, in-situ incorporation of Er into III-nitride materials by MOCVD is a very attractive method for creating highly efficient optoelectronic devices operating at 1.54 μm. We report on the experimental study and synthesis of Er doped GaN by 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⁺. The mechanisms of optical transitions involving different excitation energies, and potential applications of Er doped GaN structures in the communication wavelength are also discussed.