Enhancement of 1.5 μm emission under 980 nm resonant excitation in Er and Yb co-doped GaN epilayers

Abstract

The Erbium (Er) doped GaN is a promising gain medium for optical amplifiers and solid-state high energy lasers due to its high thermal conductivity, wide bandgap, mechanical hardness, and ability to emit in the highly useful 1.5 lm window. Finding the mechanisms to enhance the optical absorption efficiency at a resonant pump wavelength and emission efficiency at 1.5 lm is highly desirable. We report here the in-situ synthesis of the Er and Yb co-doped GaN epilayers (Er þ Yb:GaN) by metal-organic chemical vapor deposition (MOCVD). It was observed that the 1.5 lm emission intensity of the Er doped GaN (Er:GaN) under 980 nm resonant pump can be boosted by a factor of 7 by co-doping the sample with Yb. The temperature dependent PL emission at 1.5 lm in the Er þ Yb:GaN epilayers under an above bandgap excitation revealed a small thermal quenching of 12% from 10 to 300 K. From these results, it can be inferred that the process of energy transfer from Yb 3þ to Er 3þ ions is highly efficient, and non-radiative recombination channels are limited in the Er þ Yb:GaN epilayers synthesized in-situ by MOCVD. Our results point to an effective way to improve the emission efficiency of the Er doped GaN for optical amplification and lasing applications.

Enhancement of 1.5 μm fluorescence signal from Er3+ due to Yb3+ in yttrium silicate powders pumped at 975 and 808 nm

“…The enhancement factor was estimated by the ratio between the integrated intensities of the 4 I 13/2 → 4 I 15/2 fluorescence band (in the range from 1400 to 1700 nm) of the sample with Yb 3+ and the sample without Yb 3+ and we found a value of ∼5. This value is lower than the enhancement factor of ∼7 reported in [9].…”

“…The enhancement of the NIR emission around 1.5 μm via ET involving Er 3+ and Yb 3+ has been extensively studied using Yb 3+ as a sensitizer of excitation at around 980 nm [9][10][11][12]. However, in literature, a few studies have been performed on Er 3+ :Yb 3+ codoped systems pumped by photons of wavelength around 800 nm.…”

Electroluminescence from Silicon‐Based Light‐Emitting Devices with Erbium‐Doped Ta2O5 Films

“…As seen, these films all exhibit the NIR emission peaking at ≈1532 nm, arisen from the radiative transition ( 4 I 13/2 → 4 I 15/2 ) of Er 3+ ions resonantly excited by the 980 nm laser. [ 28 ] Note that the PL intensities of the Ta 2 O 5 :Er films annealed at different temperatures are almost the same, suggesting the nearly same number of luminescent Er 3+ ions accommodated in these films. However, the device with the 700 °Cannealed Ta 2 O 5 :Er film as the light‐emitting layer is not electroluminescent, the reasons for which will be given later.…”