We have grown single-crystals of (TbxY1-x)2O3 with x ≤ 0.6 by the floating zone method. The obtained crystals are substitutional solid solutions of Tb2O3 and Y2O3, and their crystal structure is of the cubic C-type. Optical spectroscopy reveals that the absorption band, originated from 4f 8 →4f75d1 transitions of Tb3+, grows inside the optical band gap of Y2O3. However, the excitation to this band is not effective for emissions of the 4f-electrons, except for low Tb-concentrations. In contrast, the bluegreen and violet-UVA excitations are sufficient, at least, up to x = 0.3.

Keywords: (TbxY1-x)2O3, Solid solution, Optical spectroscopy, Optical band gap.