Jiang Dapeng

Long-Lasting Phosphorescence Properties of Pyrochlore La2Ti2O7:Pr3+ Phosphor

The La2Ti2O7:Pr3+, which emits red color luminescence upon UV light excitation, is prepared by the conventional high-temperature solid-state method and its luminescent properties are systematically investigated. X-ray diffraction, photoluminescence, afterglow emission spectra and long-lasting phosphorescence (LLP) decay curves are used to characterize this phosphor. After irradiation by a 290-nm UV light for 3 min, the Pr3+-doped La2Ti2O7 phosphor emits intense red emitting afterglow from the 1 D2 → 3H4 transitions, and its afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source. The afterglow decay curve of the Pr3+-doped La2Ti2O7 phosphor contains a fast decay component and another slow decay one. The possible mechanism of this red light emitting LLP phosphor is also discussed based on the experimental results.

Electrical properties of zinc-oxide-based thin-film transistors using strontium-oxide-doped semiconductors*

Strontium-zinc-oxide (SrZnO) films forming the semiconductor layers of thin-film transistors (TFTs) are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide (ZnO) with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel.

Spectroscopic properties of Er/Ce-codoped La3Ga5SiO14

The Er-single-doped and Er/Ce-codoped La3Ga5SiO14 polycrystalline powders are synthesized by the solid-phase synthesis method. The room-temperature luminescence spectra of the samples are investigated. The Near-infrared-region spectroscopic properties of Er3+ ions in the La3Ga5SiO14 systems are analysed with Judd-Ofelt theory and rate equations. The effective deactivating effect of Ce3+ ions on Er3+ ions is confirmed.

Growth and spectroscopic characteristics of Nd-doped PbWO4 crystal

Nd-doped PbWO4 crystals are grown by using the modified Bridgman method. The spectroscopic properties of the crystals are investigated. The changes of the absorption band at 350 nm are discussed for samples annealed at 740 °C and 1040 °C. The radiative lifetime of the 4F3/2 level is calculated by using the Judd-Ofelt theory according to the absorption spectrum of 0.5 at.% Nd-doped PbWO4 crystal. The spontaneous Raman scattering properties of the crystals are analysed.