Intra-4f-shell transitions at room temperature of Er3+ ions in Ca1−xErxF2+x thin films grown on Si(100)

Abstract

Intra-4f-shell transitions of Er3+ ions in Ca1−xErxF2+x thin films were studied by means of photoluminescence (PL) and cathodoluminescence (CL) measurements at room temperature. The samples, with x varying from 0.01 to 0.2, were epitaxially grown on Si(100) substrates by sublimation of solid solution powders. Using the 488-nm line of an Ar+-ion laser as the excitation source, it is shown that the films present strong PL lines corresponding to the internal transitions between the 4S3/2,4F9/2,4I11/2, and 4I13/2 excited levels and the 4I15/2 fundamental state of Er3+ (4f11) ions. Their centers of gravity were pointed out at λ=533, 650, 980, and 1530 nm, respectively. These electronic transitions were also evidenced by means of the CL technique. Moreover, this technique showed that the luminescence is uniform in all points of the layers. The PL intensities vary considerably as a function of the erbium substitution rate. In the visible range the strongest luminescence was found for x less than 0.01, while for the 1530-nm line (which presents evident potential applications for optical communications) the highest luminescence intensity corresponds to x close to 0.16. The refractive index (n) of the layers also varies with the erbium concentration. For a 1.3-μm incident radiation, n continuously increases from 1.425 to 1.466 when x varies from 0.035 to 0.19. This result shows that these structures can lead to the realization of plane optical waveguides.

Observation of Rheed Intensity Oscillations During PbSe/CaF2/Si(111) MBE

“…Group Ila fluoride epitaxy on Si has been studied for a variety of applications such as insulators in high-speed electronic and optoelectronic devices, surface passivation, electron beam resist, strain-relief buffers for heteroepitaxial overgrowth, and rare-earth dopant hosts for solid-state microlaser fabrication [1,2]. Recent research efforts have been directed towards the use of ultrathin CaF 2 layers in superlattice structures for resonant tunneling devices [3].…”

Reflection high-energy electron diffraction study of the molecular beam epitaxial growth of CaF2 on Si(110)

“…1 Recently, interest has shifted towards using epitaxial fluorides as rare-earth dopant hosts for solid state microlaser fabrication. [2][3][4][5][6] For example, neodymium ͑Nd͒ 5 and erbium ͑Er͒ 6 doped CaF 2 layers grown on Si substrates have exhibited strong photoluminescence at 1.04 and 1.54 m, respectively. With suitable optical feedback cavities, it is possible to fabricate lasers on Si substrates using these materials.…”

Effect of ZnO Addition and of Alpha Particle Irradiation on Various Properties of Er3+, Yb3+ Doped Phosphate Glasses

“…The absorption spectra exhibit several bands, which are characteristics of the Er 3+ ions 4f-4f transitions from the ground state to various excited levels [19]. The absorption band at 975 nm can be also related to the Yb 3+ 4f-4f ( 2 F 7/2 → 2 F 5/2 ) transition, which overlaps with the weak absorption band due to the Er 3+ 4f-4f ( 4 I 15/2 → 4 I 11/2 ) transition.…”