Dramatic enhancement of 1.54 μm emission in Er doped GaN quantum well structures

Abstract

Erbium (Er) doped III-nitride materials have attracted much attention due to their capability to provide highly thermal stable optical emission in the technologically important as well as eye-safer 1540 nm wavelength window. There is a continued need to exploring effective mechanisms to further improve the quantum efficiency (QE) of the 1.54 lm emission in Er-doped III-nitrides. GaN/ AlN multiple quantum wells (MQWs:Er) have been synthesized by metal organic chemical vapor deposition and explored as an effective means to improve the QE of the 1.54 lm emission via carrier confinement and strain engineering. The 1.54 lm emission properties from MQWs:Er were probed by photoluminescence (PL) emission spectroscopy. It was found that the emission intensity from MQWs:Er is 9 times higher than that of GaN:Er epilayers with a comparable Er active layer thickness. The influences of the well and barrier width on the PL emission at 1.54 lm were studied. The results revealed that MQWs:Er consisting of well width between 1 and 1.5 nm and the largest possible barrier width before reaching the critical thickness provide the largest boost in QE of the 1.54 lm emission. These results demonstrate that MQWs:Er provide a basis for efficient photonic devices active at 1.54 lm. V

Telecommunication-Wavelength Lasing in Er-doped GaN Multiple Quantum Wells at Room Temperature

“…When the emission was collected from the surface, the spectra show a broad spectral feature around 1.5 µm, which is the spontaneous emission of light from Er optical centers in MQWs. As previously reported, the full-width at half-maximum (FWHM) of the 1.5 µm emission at room-temperature is 60 nm for MQWs:Er samples [13,14]. The broadening of the emission in MQWs is due to the fluctuation of the GaN quantum well width and the local atomic structures around Er optical centers.…”

“…The Er-doped GaN multiple quantum wells samples were prepared by metal organic chemical vapor deposition (MOCVD) on a c-plane sapphire substrates and had excellent material qualities [13,14]. The X-ray diffraction and photoluminescence (PL) measurements indicated that GaN:Er epilayers have high crystallinity, without second phase formation, and exhibit a strong room-temperature emission at 1.5 µm with a low degree of thermal quenching [15].…”

“…In this work, a set of 200-period Er-doped GaN/AlN multiple quantum wells (MQWs:Er) produced a significant improvement of the quantum efficiency of the 1.5 µm emission via carrier quantum confinement and strain engineering. A detail description of the growth process and epilayer structure has been reported previously [13][14][15][16][17].…”

“…The photon fluence of the Ar laser was varied from 0.05 to 120 mJ cm -2 . At low excitation pump fluence (P < 15 mJ cm -2 ), the emission at 1.5 µm shows a broad spectrum with the FWHM of 60 nm (~30 meV) which corresponds to the spontaneous emission [13]. When the pump fluence was higher (P > 15 mJ cm -2 ) the MQWs:Er samples showed a net optical gain.…”

Investigation of low-temperature cathodoluminescence mechanism of Er-doped GaN thick films by ion implantation

“…For Er-doped GaN, 537 nm and 1.54 μm emissions were both observed [6,8] . Therefore, much attention was paid to the research of Er-doped GaN materials [9,10] . The preparation method of Er-doped GaN included ion implantation [11] and in situ doping [6] .…”