Rare-earth-metal oxide films (Ln2O3; Ln=Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, and Yb) between 20 and 30 nm thick were grown on Si substrates by using a pyrolysis method. We found that a silicate (LnSiO) layer and a silicon oxide layer were formed at the interface between oxides and substrate after postannealing. The infrared absorption of the Si–O–Ln bonds increased as the postannealing temperature rose. The Si–O–Ln bond formation strongly depended on the ion radii of the rare-earth elements. We conclude that an interfacial silicate layer can easily be formed by a reaction with Si atoms diffusing from the substrate for oxides with larger ion radii. This is because such oxides may have a larger space between atoms. The quantity of Si–O–Si bonds also increased after postannealing. The increase in the Si–O–Si bonds for Ln2O3 was independent of the elements, and almost the same as the increases for Ta2O5 and ZrO2.

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Sr3Al2O6, SrAl2O4, SrAl4O7, and SrAl12O19 that have been doped with Eu2+ and Dy3+ ions have been grown by a floating‐zone technique for application as long‐duration phosphors. Long‐duration phosphorescence with a variety of colors has been observed in SrAl2O4, SrAl4O7, and SrAl12O19 crystals that have been doped with Eu2+ and Dy3+ ions. The peak wavelength of the phosphorescence is 520 nm for SrAl2O4, 480 nm for SrAl4O7, and 400 nm for SrAl12O19. The phosphorescence is characterized by decay times that have been analyzed by a curve‐fitting technique.

Erbium-related 1.54 μm emission dynamics of Er-doped ZnO thin films has been investigated for the different excitation conditions. The excitation was achieved either by exciting indirectly Er3+ ions due to an electron–hole-mediated process or exciting directly discrete energy levels of Er3+ ions. There is no change in the 1.54 μm emission spectrum feature in spite of the different excitation conditions, whereas dramatic change can be seen in the rise time of 1.54 μm emission. The shorter rise time of 1.54 μm emission observed for indirect excitation implies an excitation efficiency superior to direct excitation of Er3+ ions.

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