Luminescence of EuNa2Mg2false(VO4)3 is six times as bright as that of YVO4:normalEu under 365 nm light excitation at room temperature, but it suffers from thermal quenching at higher temperatures. The quenching is mainly caused by non‐radiative relaxation from the emitting states. Energy diffusion among the lowest excited states, 5D0 , to sinks is a main reason of relatively weak quenching below 500°K. At higher temperatures, drastic quenching due to nonradiative relaxation within each Eu3+ ion is observed. Disordered distribution of Eu3+and Na+ revealed by optical and powder x‐ray diffraction measurements is considered to induce the thermal quenching. Similar strong quenching beginning at around 500°–600°K is observed also for other disordered compounds, EuK5false(MoO4)4 and normalEuAfalse(MoO4)2 false(A=normalNa,K,normaland Rbfalse) .

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The annealing behavior of carbon implanted at 1.3 MeV with a dose of 5×1019 ions/m2 into Czochralski-grown silicon wafers is investigated using an x-ray double-crystal method, transmission electron microscopy, secondary-ion-mass spectroscopy, and infrared-absorption spectroscopy. For comparison, the behavior of boron implanted at 2.0 MeV with 5×1019 ions/m2 is also investigated. X-ray rocking curve analysis shows that carbon produces a larger lattice strain than boron. For the samples annealed at 1273 K, x-ray data indicate that the carbon atoms, unlike the boron atoms, do not occupy substitutional sites. In addition, the present experimental data suggest that the interaction of interstitial carbon atoms with silicon self-interstitials produced by ion implantation suppresses the generation of dislocations and brings about the reduction of lattice strain in the implanted region.

Die Lumineszenz der Titelverbindung ist unter 365 nm‐Anregung bei 25°C 6mal heller als die von YVO4:Eu; allerdings tritt bei höheren Temp. thermische Löschung auf.

Precise lattice parameter measurements have been made for semi-insulating GaAs, and it is found that the lattice parameters vary greatly (order of 10-4 Å) among GaAs wafers and in a wafer. This variation of lattice parameter is closely related to the threshold voltage of the FETs, which are made by direct ion implantation on the crystal. The change of the lattice constant is probably caused by the interstitial As atoms, and a slight change of crystal growth condition may cause its variation in the wafer. Variation of the As concentration affects the threshold voltage of MESFETs when they are made by direct ion implantation.