Laser-heated pedestal growth of cerium doped calcium scandate crystal fibers

TL;DR

This paper reports the first successful growth of Ce3+ doped calcium scandate single crystals using laser heated pedestal growth, highlighting the importance of nitrogen atmosphere purity and growth conditions for optical properties.

Contribution

It introduces a novel crystal growth method for CaSc2O4:Ce3+ and analyzes how growth atmosphere affects cerium valence and optical emission.

Findings

Laser heated pedestal growth is suitable for CaSc2O4:Ce3+ in high-purity nitrogen.

Oxygen levels influence cerium valence state and optical emission.

Optimal growth conditions enable stable crystal growth and desired optical properties.

Abstract

Ce3+ doped oxide materials are promising for optical emission in the green spectral range. The growth of CaSc2O4:Ce3+ single crystals is reported here for the first time. Laser heated pedestal growth (LHPG) proved to be suitable for this refractive material, if performed in nitrogen of 99.999% purity. If the oxygen content of the growth atmosphere is substantially larger, Ce4+ is formed, which shows no useful optical emission. If the oxygen content is substantially lower, severe evaporation of calcium impedes stable crystal growth. Thermodynamic equilibrium calculations allowed to describe evaporation of species and cerium dopant charging under different growth conditions. The evaporation could be investigated by quadrupole mass spectrometry of emanating gases and by chemical analysis of fibers with ICP-OES. The congruent melting point was confirmed by DTA at 2110 degrees centigrade. Photoluminescence spectrometry of fibers revealed the dependence of optical emission in the green spectral range on growth conditions.