Crystal-field split levels of Nd3+ ions in GaN measured by luminescence spectroscopy

Abstract

We present the Stark energy sublevels of Nd3+ ions in GaN grown by plasma-assisted molecular beam epitaxy as determined by luminescence spectra. We correlate the photoluminescence spectra with transitions from the F43/2 excited state to the I49/2, I411/2, and I413/2 multiplets of the Nd3+ ion for above and below bandgap excitation, with the strongest emission occurring at 1.12 eV (1106 nm). We determine a splitting of the F43/2 excited state to be 4.1 meV. From photoluminescence excitation spectra, we also identify the Stark sublevels of the upper states F45/2, H29/2, F47/2, S43/2, G27/2, and G45/2. Photoluminescence excitation spectra reveal an optimal excitation energy of 1.48 eV (836 nm). Site-selective spectroscopy studies using combined excitation-emission spectroscopy with confocal microscopy indicate enhanced substantial doping at the Ga site.

Electronic structure analysis of rare earth ions Ce and Nd doped gallium nitride

“…RE dopants in GaN are alternative sources of visible light emission particularly for green light other than the prime source InGaN in order to avoid the problems related to the growth of InGaN with high In content. [7][8][9][10][11][12][13][14] The synthesis of Nd doped GaN by plasma-assisted molecular beam epitaxy was reported by Readinger et al 15 Metcalfe et al studied the optical characterization of Nd 3þ emission spectra 16 and Gruber et al studied the stark levels of Nd doped GaN. 17 All these efforts along with further future investigations could lead to the further development of first pumped Nd doped GaN laser diode which will have highest laser efficiency because of pumping action.…”

Crystal-field analysis and Zeeman splittings of energy levels of Nd3+ (4f3) in GaN

“…[12][13][14] A detailed study of the spectra and the crystal-field splitting of Yb 3þ in AlN has been reported more recently by Koubaa et al 15 Recently, Readinger et al 16 reported the fabrication of in situ doping of GaN with Nd by plasma-assisted molecular beam epitaxy (PA-MBE). Metcalfe et al 17 followed this work with an optical characterization of the observed Nd 3þ emission spectra. Using site-selective excitation methods, Metcalfe et al 17 identified several Nd 3þ sites in the doped samples, including a majority site, which they suggested contained Nd 3þ ions that had replaced Ga 3þ ions in cation sites having C 3v symmetry in undoped GaN.…”

“…Metcalfe et al 17 followed this work with an optical characterization of the observed Nd 3þ emission spectra. Using site-selective excitation methods, Metcalfe et al 17 identified several Nd 3þ sites in the doped samples, including a majority site, which they suggested contained Nd 3þ ions that had replaced Ga 3þ ions in cation sites having C 3v symmetry in undoped GaN. The set of experimental crystal-field split energy (Stark) levels identified as the "main" site in Ref.…”

“…The set of experimental crystal-field split energy (Stark) levels identified as the "main" site in Ref. 17, were used in the present study to model the crystal-field splitting of the 2Sþ1 L J multiplet manifolds of Nd 3þ , which include the ground-state manifold, 4 I 9/2 , and the excited manifolds 4 I 11/2 , 4 I 13/2 , 4 F 3/2 , 4 F 5/2 , 2 H 9/2 , 4 F 7/2 , 4 S 3/2 , 4 G 5/2 , and 2 G 7/2 .…”

Nanoscale determinant to brighten up GaN:Eu red light-emitting diode: Local potential of Eu-defect complexes

“…The PL properties of the Eu dopants in a GaN:Eu thin film have already been well-investigated using two types of photoexcitation: resonant (direct) excitation of Eu 4f levels and indirect excitation of the levels via the interband transition of the GaN host. 19,20 For the direct excitation, an advanced technique, combined excitation-emission spectroscopy (CEES), 22,23 in which the continuous tuning of the excitation energy and recording of the respective emission spectra provide two-dimensional PL spectral maps, revealed static characteristics of each of the eight Eu emission sites. In the following discussion, we refer to the characteristics in order to understand intensity of the emission sites for the current injection.…”