The influence of oxygen content on photoluminescence from Er-doped SiOx

SiOx films with oxygen concentrations ranging 13-46 at.% were deposited by plasma enhanced chemical vapor deposition (PECVD) technique using: pure SiH4 and N2O mixture. Erbium was then implanted at an energy of 500 KeV with dose of 2x10(15) ions/cm(2). The samples were subsequently annealed in N-2 for 20 sec at temperatures of (300-950 degrees C). Room temperature (RT) photo-luminescence (PL) data were collected by Fourier Transform Infrared Spectroscopy (FTIS) with an argon laser at a wavelength of 514.5 nm and an output power from 5 to 2500 mw. The intense room-temperature luminescence was observed around 1.54 mu m. The luminescence intensity increases by 2 orders of magnitude as compared with that of Er-doped Czochralski (CZ) Si. We found that the Er3+ luminescence depends strongly on the SiOx microstructure. Our experiment also showed that the silicon grain radius decreased with increasing oxygen content and finally formed micro-crystalline silicon or nano-crystalline silicon. As a result, these silicon small particles could facilitate the energy transfer to Er3+ and thus enhanced the photoluminescence intensity.

Study of infrared luminescence from Er-implanted GaN films

In this study, we report the dependences of infrared luminescence properties of Er-implanted GaN thin films (GaN:Er) on the kinds of substrates used to grow GaN, the growth techniques of GaN, the implantation parameters and annealing procedures. The experimental results showed that the photoluminescence (PL) intensity at 1.54 mum was severely influenced by different kinds of substrates. The integrated PL peak intensity from GaN:Er /Al2O3 (00001) was three and five times stronger than that from GaN:Er /Si (111) grown by molecular beam epitaxy (MBE) and by metalorganic chemical vapor deposition (MOCVD), respectively. The PL spectra observed from GaN:Er/Al2O3 (0001) grown by MOCVD and by MBE displayed a similar feature, but those samples grown by MOCVD exhibited a stronger 1.54 mum PL. It was also found that there was a strong correlation between the PL intensity with ion implantation parameters and annealing procedures. Ion implantation induced damage in host material could be only partly recovered by an appropriate annealing temperature procedure. The thermal quenching of PL from 15 to 300 K was also estimated. In comparison with the integrated PL intensity at 15 K, it is reduced by only about 30 % when going up to 300 K for GaN:Er/Al2O3 sample grown by MOCVD. Our results also show that the strongest PL intensity comes from GaN:Er grown on Al2O3 substrate by MOCVD. (C) 2004 Elsevier B.V. All rights reserved.

Correlation between Er3+ emission and the microstructure of a-SiOx : H < Er > films

Photoluminescence (PL) from Er-implanted hydrogenated amorphous silicon suboxide (a-SiOX:H<Er>(x<2.0)) films was measured. Two luminescence bands with maxima at lambda congruent to 750 nm and lambda congruent to 1.54mum, ascribed to the a-SiOX:H intrinsic emission and Er3+ emission, were observed. Peak intensities of the two bands follow the same trend as a function of annealing temperature from 300 to 1000degreesC. Micro-Raman results indicate that the a-SiOX:H<Er> films are a mixture of two phases, an amorphous SiOX matrix and amorphous silicon (a-Si) domains embedded there in. FTIR spectra confirm that hydrogen effusion from a-SiOX:H<Er> films occurs during annealing. Hydrogen effusion leads to a reconstruction of the microstructure of a-Si domains, thus having a strong influence on Er3+ emission. Our study emphasizes the role of a-Si domains on Er3+ emission in a-SiOX:H<Er> films.

Experimental study of the beta-delayed proton decays of Er-145,Er-147

The beta-delayed proton decays of Er-145,Er-147 have been studied experimentally using the Ni-58 + Mo-92 reaction at beam energy of 383 MeV. On the basis of a He-jet apparatus coupled with a tape transport system, the beta-delayed proton radioactivities both from the nu s(1/2) ground state and the nu h(11/2) isomer in Er-145,Er-147 were observed by proton-gamma coincidence measurements. By analyzing the time distributions of the 4(+) -> 2(gamma)(+) transitions in the granddaughter nuclei Dy-144,Dy-146, the half-lives of 1.0 +/- 0.3 s and 1.6 +/- 0.2 s have been deduced for the nu h(11/2) isomers in Er-145,Er-147, respectively.

Properties of the beta-Delayed Proton Decay of Er-147

The beta-delayed proton decay of Er-147 is studied experimentally using the Ni-58+Mo-92 reaction at a beam energy of 383 MeV. Based on a He-jet apparatus coupled with a tape transport system, the beta-delayed proton radioactivities both from the nu s(1/2) ground state and the nu h(11/2) isomer in Er-147 are identified by proton-gamma coincidence measurements. By analyzing the time distribution of the 4(+) -> 2(+) gamma transition in the grand-daughter nucleus Dy-146, a half-life of 1.6 +/- 0.2 s is determined for the nu h(11/2) isomer in Er-147. The half-life for the ground state of Er-147 is estimated to be 3.2 +/- 1.2 s.

~(145)Er的β延发质子衰变性质研究；Properties of β-delayed Proton Decay of ~(145)Er

通过92Mo(58Ni,2p3n)熔合蒸发反应生成了非常缺中子核145Er。利用氦喷嘴带传输系统把研究目标核传输到低本底测量站,进行了质子-γ符合测量,得到了不受同量异位素干扰的145Er的β延发质子谱。经过仔细分析与延发质子符合的γ谱,发现了145Er的11/2-同核异能态具有β延发质子衰变性质。经拟合退激144Dy不同激发态γ跃迁的衰变曲线,得出145Er的1/2+基态和11/2-同核异能态的半衰期分别为(1.6±0.6)和(0.6±0.1)s。最后,简单介绍了中重质量区缺中子新核素的合成及衰变研究计划。

~(153)Er, ~(157)Yb(EC+#beta#~+)衰变纲图的首次建立

用蒸发中子反应产生~(157)Tb和~(153)Er，收集活性样品，作x, #gamma# 单谱及符合谱测量，对~(157)Yb和~(153)Er的(EC+#beta#~+)衰变进行了研究，给出了~(157)Yb及~(153)Er的衰变纲图，其中~(157)Yb的衰变纲图包括25条新#gamma#射线，分析~(157)Yb的衰变纲图，~(153)Er的衰变纲图包括15条#gamma#射线，并指定出~(153)Er半衰变期值，该值与文献给出值符合得很好。指定了~(153)Er的衰变纲图中能级状况

缺中子同位素~(153)Er和~(157)Yb的（EC/β~+）衰变纲图

利用142Nd（16O，5n）153Er和147Sm（16O，6n）157Yb反应并藉助与氦喷嘴快速带传输装置和x(γ) γt-符合测量技术首次建立了153Er和157Yb的（EC/β+）衰变能级纲图。 对153Er的（EC/β+）衰变纲图的分析，得到结果有， 1） 辨认了256.7KeV和634.2KeV的二条低位能级分别为d3/2和d5/2的单质子态。因此，153H0的基态 的形状为球形。在同位素链Ho（Z=67）上，随着中子数的增加，奇质量数Ho核的基态核形状由球形过渡到变形发生在中子数86和88之间。 2） 位于1700.1KeV能级为三粒子态，具有[(πh11/2 νh9/2)1+ νf7/2] ， ， 的结构特征。 经对157Yb的（EC/β+）衰变纲图分析，得到结果有， 1） 发现了建立在157Tm基态上的Kπ= 转动带的带头部分。用可变转动惯量的三轴行变粒子转子模型对157Tm的转动能谱的计算结果表明，157Tm的基态Kπ= 转动带所对应的形变是三轴形变，相应的形变参数为ε2=0.23，ε4=0.01，γ=35°。给出了随着中子数的增加，奇质量数Tm（Z=69）核的基态核形状由球形过渡到非球形发生在中子数86和88之间。 2） 辨认了一条位于激发能为3502KeV的同质异能态，其寿命>40ns。

基于ER Mapper的水土流失地形因子提取技术初探

介绍了新一代图像处理系统ERMapper及其应用 ,分析了不同空间尺度下影响水土流失的地形因子。针对ERMapper的图像处理功能 ,对地形因子的提取技术进行了初步探讨 ,并取得了一定成果

Age hardening and mechanical properties of Mg-Gd-Er alloy

The Mg-8Gd-0.6Zr-xEr (x = 1, 3 and 5 mass%) alloys were prepared by casting technology, and the microstructures, age hardening behaviors and mechanical properties of alloys have been investigated. Microstructures of the alloys are characterized by the presence of rosette-shaped equiaxed grains. The age hardening behaviors and the tensile properties are enhanced by adding Er element. The maximum aged hardness of Mg-8Gd-0.6Zr-5Er alloy is 97, it is nearly 1.24 times higher than that of Er-free alloy.

Novel Near-Infrared Luminescent Hybrid Materials Covalently Linking with Lanthanide [Nd(III), Er(III), Yb(III), and Sm(III)] Complexes via a Primary beta-Diketone Ligand: Synthesis and Photophysical Studies

A series of novel, colorless, and transparent sot-gel derived hybrid materials Ln-DBM-Si covalently grafted with Ln(DBM-OH)(3)center dot 2H(2)O (where DBM-OH = o-hydroxydibenzoylmethane, Ln = Nd, Er, Yb, and Sin) were prepared through the primary beta-diketone ligand DBM-OH. The structures and optical properties of Ln-DBM-Si were studied in detail. The investigation results revealed that the lanthanide complexes were successfully in situ grafted into the corresponding hybrids Ln-DBM-Si. Upon excitation at the maximum absorption of ligands, the resultant materials displayed excellent near-infrared luminescence.

Near-infrared luminescent xerogel materials covalently bonded with ternary lanthanide [Er(III), Nd(III), Yb(III), Sm(III)] complexes

A beta-diketone ligand 4,4,5,5,5-pentafluoro-1-(2-naphthyl)-1,3-butanedione (Hpfnp), which contains a pentafluoroalkyl chain, was synthesized as the main sensitizer for synthesizing new near-infrared (NIR) luminescent Ln(pfnp)(3)phen (phen = 1,10-phenanthroline) (Ln = Er, Nd, Yb, Sm) complexes. At the same time, a series of lanthanide complexes covalently bonded to xerogels by the ligand 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (phen-Si) were synthesized in situ via a sol-gel process. [The obtained materials are denoted as xerogel-bonded Ln complexes (Ln = Er, Nd, Yb, Sm).] The single crystal structures of the Ln(pfnp) 3phen complexes were determined.

Synthesis and characterization of monodisperse spherical SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles with core-shell structure

Spherical SiO2 particles have been coated with rare earth oxide layers by a Pechini sol-gel process, leading to the formation of core-shell structured SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence spectra as well as lifetimes were used to characterize the resulting SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Eu3+, Tb3+, Dy3+, Sm3+, Er3+, Ho3+) samples. The obtained core-shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 380 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (40 nm for two deposition cycles).